Pedigree lingo: Phrases to known in horse racing

April 5th, 2023

Have you ever found yourself overwhelmed by the lingo pertaining to racehorse pedigrees? Words like “sire,” “dam,” and “broodmare” don’t necessarily mean a lot to those unfamiliar with horses or the sport.

Fortunately, the lingo isn’t as complicated as it sounds. To speed up the learning process, we’ve compiled a handy list of common terms used to describe racehorse pedigrees and relations.


The ancestry of a racehorse. A pedigree lists the parents, grandparents, great-grandparents, etc., typically going back four or five generations. The father’s side of the pedigree is displayed on top; the mother’s side is listed on the bottom.


The father of a horse.


A male horse who sires foals.


The horses sired by a stallion.


The mother of a horse.


Whereas a stallion sires foals, a dam produces foals.

Mare, or broodmare

A female horse who produces foals.

Dam sire, or broodmare sire

The maternal grandfather of a horse—in other words, the sire of the dam.

Second dam

The maternal grandmother of a horse—in other words, the mother of the dam. Third dam refers to the maternal great-grandmother, fourth dam to the maternal great-great grandmother, etc.

“[Name]–[Name], by [Name]”

A common format used to describe the key ancestors in a pedigree. If a horse’s sire is Curlin, and their dam is Dreaming of Julia, and their dam sire is A.P. Indy, their pedigree will be described as “Curlin–Dreaming of Julia, by A.P. Indy.”

“Sire: [Name] ([Name])” or “Dam: [Name] ([Name])”

Another common format used to describe the key ancestors in a pedigree. In this case, the name of the sire or dam is followed in parenthesis by their sire. Using the previous example, with the added info that Curlin’s sire is Smart Strike, you might see the pedigree listed as “Sire: Curlin (Smart Strike)” and “Dam: Dreaming of Julia (A.P. Indy).”


This one is clear enough. When two horses share the same sire and dam, they are full-siblings.


Half-sibling is a trickier term. Since top stallions sire thousands of foals in their lifetime, horses that share the same sire are not referred to as half-siblings, even though they technically are half-siblings. In horse racing, half-sibling refers to horses who share the same dam.


If the pedigree of a horse contains one ancestor in multiple places - usually inside the horse's first five generations - the pedigree is said to contain inbreeding. For example, the breed-shaping stallion Mr. Prospector appears in many pedigrees. If a stallion and a broodmare who descend from Mr. Prospector are mated, the resulting foal will be related to Mr. Prospector through multiple pedigree paths. That's inbreeding.

Duplication/Cross, "[Number] x [Number]"

You may also see the terms "duplication" or "cross" to describe the appearance of horses on multiple occasions in a pedigree, along with expressions such as 4x4, 5x5, or similar. In the example below, of leading sire Tapit, where Mr. Prospector features in both the fourth and fifth generation of the pedigree, Tapit is said to carry a 4x5 duplication or cross of Mr. Prospector.

The pedigree of acclaimed stallion Tapit, showing inbreeding (marked in red) to Mr. Prospector.

Now that you’re up to speed on key pedigree terms, be sure to check out the pedigree section of TwinSpires Edge to read about newsworthy racehorses and their pedigrees.