Definition
A young female horse; a female colt that has not yet reached full maturity. In legal usage, the term carries a precise zoological meaning distinguishing a young mare from an adult mare. The distinction is not merely descriptive — it is operative in criminal pleading, where a charge specifying "filly" cannot be sustained by proof involving an adult mare.
Common Language
Modern common usage (Wiktionary): A young female horse; informally, a young attractive woman.
Historical common usage (Webster's 1913): A female foal or colt; a young mare. Also used colloquially to mean a lively, spirited young girl.
The common meaning and the legal meaning are closely aligned in their core sense, but the legal context demands a level of precision that ordinary usage does not. In conversation, "filly" and "mare" may be used loosely or interchangeably by non-specialists. In a criminal indictment, they are not interchangeable — the specific animal described in the charging instrument must correspond to the animal proven to have been taken.
Common Confusion
FILLY vs. MARE: The practical legal risk here is in criminal pleading. A mare is an adult female horse; a filly is a young female horse that has not yet reached full maturity. Both dictionaries and the single reported case in this record confirm that these are legally distinct terms. Proof of the larceny of a mare will not sustain an indictment drawn for the theft of a filly. Researchers should not assume that references to a "mare" in witness testimony or property records are interchangeable with "filly" in a charging document.
Why It Matters in Research
The legal significance of this term is narrow but sharp: it is a pleading precision issue in criminal law, specifically larceny of livestock. Nineteenth-century American criminal practice required that indictments describe stolen property with specificity, and animal terminology was part of that specificity. A misdescription — charging theft of a filly when the animal was in fact a mature mare — could be fatal to a prosecution.
Researchers working with historical criminal records involving livestock theft should attend carefully to the age and sex descriptors used in indictments versus those appearing in trial evidence and witness statements. Discrepancies that appear trivial to a modern reader may reflect deliberate or accidental variance that affected case outcomes.
The Texas case cited uniformly across all three source dictionaries (1 Tex. App. 448) appears to be the anchor authority for this principle in American legal sources. Researchers relying on this point in jurisdictions other than Texas should treat it as instructive but confirm whether their jurisdiction applied equally strict variance rules in livestock indictments.
Outside of criminal pleading, the term may appear in agricultural contracts, estate inventories, livestock sale agreements, and insurance records. In those contexts, precision of age and sex description affects valuation, warranty, and identity of the subject matter — disputes over whether a sold or insured animal qualified as a "filly" rather than a "mare" at the time of contract are plausible in historical agrarian records.
Historical Dictionary Support
All three source dictionaries — Black's (1st Ed.), Black's (2nd Ed.), and Bouvier's — supply identical substantive definitions and cite the same Texas authority. There is no meaningful divergence among them on this term. The consistency suggests the definition was settled and uncontested in the period when these dictionaries were compiled.
Black's 2nd Edition adds the full citation: Lunsford v. State, 1 Tex. App. 448, 28 Am. Rep. 414, giving researchers a more complete reference than the abbreviated form in Black's 1st and Bouvier's.
None of the historical dictionaries address the term beyond its criminal pleading application. Contractual, probate, or commercial uses are not discussed, leaving a gap for researchers working outside the larceny context.
Jurisdictional Note
The only authority cited in the historical legal dictionaries is a Texas appellate decision. The pleading variance principle it represents — that proof must match the specific animal described in the indictment — was a general feature of nineteenth-century common law criminal procedure, but its application to livestock terminology varied by jurisdiction and by how strictly individual courts enforced variance doctrine.