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Colt and Filly: Learn to Use Horse Terms in Context

Last updated: November 28, 2023

By: Miles HenryFact Checked

Have you ever heard horse enthusiasts talk about ‘colts,’ ‘fillies,’ ‘foals,’ ‘yearlings,’ and ‘weanlings’? Each of these terms has a special meaning in the horse world. The most common terms, colt and filly, specifically refer to young male and female horses under four years old.

Under one year old, all horses are ‘foals,’ regardless of gender. As they grow, they become known as ‘yearlings’ and then ‘weanlings’ at different stages of their youth. These terms are essential for understanding and talking about young horses correctly. So, let’s get started and learn how to use horse terms just like the experts do.

Picture of a foal in a meadow.

Understanding the Basics

Let’s start with the fundamentals: understanding the terms ‘foal,’ ‘colt,’ and ‘filly.’ This section will break down these basic yet essential horse terms, providing a clear foundation for anyone interested in equine terminology.

Defining ‘Foal’

A ‘foal’ is a term used for any young horse, regardless of gender, that is under one year old. This is the most general term we use when talking about newborn horses. Foals are known for their playful behavior and rapid growth. During their first year, they learn to walk, run, and develop strong bonds with their mothers. Remember, whether it’s a young male or female horse, if it’s under one year old, it’s called a foal.

What is a ‘Colt’

Now, let’s talk about ‘colts.’ A colt is a young male horse, specifically under the age of four. Colts can be easily recognized by their spirited and energetic nature. They are usually taller and more muscular than fillies, with a distinctively robust build as they grow older. In their early years, colts start to show signs of their adult characteristics and behaviors. It’s important to use the term ‘colt’ correctly – it’s only for young male horses.

What is a ‘Filly’

On the other side, we have ‘fillies.’ A filly is a young female horse, also under the age of four. Fillies are generally more delicate and refined in their build compared to colts. They are known for their grace and agility, often showing a calmer demeanor than colts. Like colts, fillies grow quickly, but their physical and behavioral development has its unique aspects. Understanding the term ‘filly’ is crucial, as it specifically refers to young female horses.

It’s essential to get these terms right, as they are foundational in the world of equine knowledge.

ColtMaleFour Years and youngerNot castrated
FillyFemaleFour Years and younger
FoalEither sexLess than one-year-old
WeanlingEither sexTypically between 4-7 monthsStopped sucking milk
YearlingEither sexBetween 1 and 2 years old
Picture of a two year old filly.
Two-year-old filly

Colts and Fillies: A Detailed Look

Let’s dive deep into the world of young horses. Here, we explore the unique physical and behavioral traits of colts and fillies and uncover how genetics and environment shape their development.

Physical and Behavioral Differences Between Colts and Fillies

When it comes to physical and behavioral characteristics, colts and fillies show distinct differences. Colts, the young males, are often more muscular and robust in their build. They tend to be more adventurous and energetic, showing a greater tendency towards playfulness and dominance as they grow.

On the other hand, fillies, which are young female horses, usually have a more refined physique. They are often more graceful and agile, with behaviors that lean towards calmness and alertness.

The Role of Genetics and Environment in Their Development

Both genetics and environment play crucial roles in the development of colts and fillies. Genetics determine the physical traits, such as coat color, height, and build, inherited from their parents.

Meanwhile, the environment, including the care they receive, nutrition, and social interactions, significantly influences their behavior and health. For instance, a colt raised in a nurturing environment with ample space to roam and play will develop differently from one raised in confined spaces.

Common Misconceptions About Colts and Fillies

There are several misconceptions about colts and fillies. One common myth is that colts are always aggressive and fillies are always gentle, but personality can vary widely within each gender. Another misconception is that all young horses are colts, which, as we know, is not true.

The term ‘colt’ is specific to young male horses, not a general term for all young horses. Understanding these differences and common myths helps in appreciating the unique qualities of each young horse.

Picture of a colt.
Two-year-old colt

Beyond Colt and Filly: Other Young Horse Terms

Moving beyond colts and fillies, this section introduces you to other essential terms like ‘yearling’ and ‘weanling.’ Understand the stages of a young horse’s life and how these terms vary across different horse communities and cultures.

Yearling Explained

After a horse has celebrated its first birthday but before it turns two, it’s known as a ‘yearling.’ This term is quite straightforward; it literally refers to a horse that is a year old. Yearlings are no longer considered foals, as they’ve moved past infancy into a more developed juvenile stage.

At this age, they’re learning more about social behavior grazing and may begin early training. Physically, yearlings continue to grow rapidly, though they’re not yet at their full adult size or strength. Unlike foals, yearlings are more independent but still require careful nurturing and training.

Picture of a colt and filly with a broodmare.
Young horses with a broodmare.

Defining a ‘Weanling’

‘Weanling’ is another term you might hear, and it refers to a horse that has been weaned from its mother’s milk but is not yet a year old. This is a crucial stage in a horse’s life, as it marks the transition from relying solely on the mother for nutrition to eating solid food like grass and grains.

Weanlings undergo significant physical and psychological changes during this period as they adapt to life without their mother’s constant presence and learn to socialize with other horses.

Usage in Different Horse Communities and Cultures

Different horse communities and cultures might use these terms with slight variations or emphasize different aspects of their care and development. For example, in racing communities, the age and development stage of yearlings and weanlings can be crucial for training schedules and preparations for future racing careers.

In contrast, in a more traditional ranching setting, the emphasis might be more on the social integration of these young horses into the herd. Understanding how these terms are applied in various contexts can provide deeper insights into horse care and culture globally.

Picture of a racing form.
Racing form.

Colts in horse racing

In horse racing forms, a male racehorse between two and four years old is listed as a colt unless castrated; then, it is listed as a gelding. Once it reaches five, it is listed in the racing forms as a horse. In the photo above, the horses are listed by color, gender, and age. Number 4 is a 5-year-old bay horse, and Number 5 is a 4-year-old chestnut gelding.

Origin of the word “colt.”

The word “colt” to describe horses can be traced to Old English colt “a young horse,” also “young ass.,” In some Bible translations, it is also used for “young camel.”

There are many other possibilities for the etymology of the word colt. For example, “colt” could have derived from Proto-Germanic *kultaz or the Swedish word Kult meaning “young boar, piglet; boy,” to Danish’s use of kuld as a descriptor for young or inexperienced persons from early 13c.  

What does Colt mean in slang?

While you can use the word colt to describe a young, inexperienced male, it’s more commonly associated with describing an arrogant man who struts around.

Picture of a three-year-old racing filly I recently bought.
Three-year-old filly

Fillies in Horse Racing

In racing forms, female horses four years old and younger are listed as fillies. Many races are restricted to fillies and mares. I recently bought a three-year-old filly named Mindy; she is running her second race this month; it is a maiden claiming restricted to fillies and mares; that’s her in the picture.

However, it’s not unusual for fillies to compete against their male counterparts and be successful. Some of the greatest racehorses were females, such as Ruffian and Winx, and a few even won the Kentucky Derby.

What does filly in slang mean?

The term “filly” dates back to the 18th century when it was used as a synonym for a mischievous child or young woman with quick wit and energy. Over time, this sense of the word has fallen out of usage due to its sexist implications. However, if you’re looking for a word that still captures the characteristics of good-looking young women with quick wit fillies, work!

Picture of a chesnut baby horse.
Quarter horse weanling

Practical Application: Using These Terms Correctly

In the world of horses, using the right terminology not only shows respect for the animals but also enhances communication within the equestrian community. This section offers practical advice on how to use terms like ‘colt,’ ‘filly,’ ‘foal,’ ‘yearling,’ and ‘weanling’ correctly, helping you navigate various horse-related situations with confidence.

Situational Examples: When to Use Each Term Appropriately:

  • Foal: Use this term when referring to any horse under one year old, regardless of gender. For example, when you see a young horse that’s just a few months old, whether it’s male or female, you can correctly call it a foal.
  • Colt: This is the right term for a male horse under the age of four. If you’re at a farm and see a young male horse that’s about three years old, ‘colt’ is the appropriate term to use.
  • Filly: Similarly, use ‘filly’ for a female horse under four years old. So, if you’re watching a horse race and the commentator mentions a three-year-old female horse, they’re referring to a filly.
  • Yearling: This term applies to horses between one and two years old. For example, if a horse has just celebrated its first birthday but isn’t two yet, it’s a yearling.
  • Weanling: Use ‘weanling’ for a horse that’s been weaned off its mother’s milk but hasn’t reached its first birthday. At horse auctions, weanlings are often sold once they are weaned, which is typically around six months of age.

Common Mistakes to Avoid in Using These Terms:

  • One of the most common mistakes is using ‘colt’ to refer to all young horses, regardless of gender. Remember, ‘colt’ is specific to young males.
  • Another error is confusing ‘filly’ and ‘foal.’ While all fillies are foals (if they’re under one year old), not all foals are fillies, as the term also includes young males.
Picture of yearlings in a field.
Yearlings grazing.

Tips for Remembering and Applying These Terms in Everyday Conversation:

  • Associate the terms with their specific characteristics: ‘colt’ with young males and ‘filly’ with young females.
  • Think of ‘foal’ as a baby horse, applicable to all horses under one year, and ‘yearling’ as the toddler term for horses in their second year of life.
  • Remember that ‘weanling’ marks a significant milestone in a horse’s early life – the transition from milk to solid food.

By understanding and using these terms correctly, you’ll be able to communicate more effectively about horses and show your knowledge and respect for these magnificent animals.

Origin of the word “foal.”

The word “foal” comes from Old English, Fola meaning small or little. It is also related to other terms, such as Vulon in Dutch, which means baby or child.

Below is a cute YouTube video of a newborn foal taking its first steps.

YouTube video


Mastering horse terminology, especially terms like ‘colt,’ ‘filly,’ ‘foal,’ ‘yearling,’ and ‘weanling,’ enriches your understanding and appreciation of these magnificent animals. Whether you’re a horse enthusiast, a casual observer, or someone new to the equine world, using these terms correctly enhances communication and shows respect within the horse community.

Remember, each term carries its own significance and is an essential part of the vibrant tapestry of horse culture. As you continue your journey in the world of horses, let this knowledge guide your conversations and interactions, helping you connect more deeply with these incredible creatures and their enthusiasts.


What is a weanling?

A weanling is a baby horse that has been weaned from its mother. In other words, it’s a horse that recently stopped nursing and began eating solid food. A weanling can be any type of mammal, but most commonly refers to young horses.

What is a yearling?

The yearling is a horse that is between the ages of one and two. The term “yearling” often refers to young horses who have been weaned from their mother’s milk, but it can also refer to any animal in its first year of life.