Definition
Per cent (also written percent or per centum) means a proportion or rate expressed as parts per hundred. A statement that interest accrues at "six per cent" means six parts out of every hundred — that is, six-hundredths of the principal. In legal instruments, contracts, statutes, and financial documents, per cent functions as a precise mathematical unit for expressing rates of interest, tax rates, commission, penalties, statutory thresholds, ownership shares, and voting requirements.
The term appears in both spelled-out form ("per cent," "per centum") and symbolic form (%). In older legal documents, "per centum" is the more formal Latin rendering; "per cent" is its anglicized contraction; "percent" (one word) is the modern standard. All three forms carry identical legal meaning.
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Common Language
Modern common usage (Wiktionary): A variant form of "percent," meaning a proportion out of one hundred, expressed with the symbol %.
Historical common usage (Webster's 1913): "By the hundred; as, ten per cent means ten in the hundred, whether of gain, loss, or interest."
The common and legal meanings of per cent are essentially the same in substance. The gap lies in precision of expression. In ordinary speech, "percent" is informal and approximate; in legal instruments, the same figure carries binding force — a rate of "ten per cent per annum" in a promissory note creates an enforceable obligation calculated to the decimal. Researchers should not assume that looseness in everyday usage carries over into legal documents where the figure is operative.
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Why It Matters in Research
The primary research challenge with per cent is not definitional ambiguity but notational variation across historical sources. In documents predating the twentieth century, "per centum" is standard; "per cent." with a terminal period (treating it as an abbreviation) is common in nineteenth-century legal printing; "percent" as a single word is a twentieth-century consolidation. When searching historical statutes, deeds, mortgage instruments, or reported decisions, researchers must account for all three spellings and the symbolic form to avoid missing relevant passages.
Statutory rate provisions are a specific trap. Interest rate caps, usury limits, tax rates, and penalty provisions expressed in per cent terms have changed frequently. A researcher reading an 1880s contract or statute must confirm what per cent figure applied under the law then in force — not assume modern rates. Many historical usury statutes set ceilings in per centum terms that have since been preempted, repealed, or extensively modified.
In corporate and securities law, per cent thresholds govern material rights: majority and supermajority voting, triggering disclosure obligations, defining control, and establishing ownership thresholds for regulatory filings. These statutory and regulatory thresholds are jurisdiction- and instrument-specific. The same percentage figure may carry entirely different legal consequences depending on context — a five per cent ownership stake triggers different obligations under federal securities regulation than under a state corporate statute.
The symbolic "%" is functionally interchangeable with "per cent" and "per centum" in modern instruments, but researchers working with older printed materials should be alert to typeface and transcription errors that can corrupt percentage figures in digitized sources. A dropped digit or misread fraction in a rate provision is a meaningful error, not a trivial one.
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Historical Dictionary Support
Black's Law Dictionary (2nd Ed.) defines per cent as an abbreviation of the Latin "per centum," meaning "by the hundred, or so many parts in the hundred, or so many hundredths." The entry is terse, which reflects the term's basic mathematical clarity — there is little doctrinal content to expound. Black's cites Blakeslee v. Mansfield, 66 Ill. App. 119, and a provision of the Virginia Code, suggesting the entry was prompted by questions of usage and abbreviation in legal instruments rather than by any contested legal meaning.
Historical legal dictionaries are consistent on the core definition and largely silent on nuance, because the term's legal significance flows entirely from context — what instrument it appears in, what rate it expresses, and what law governs that instrument. The historical sources do not address the modern consolidation to single-word "percent," nor the widespread adoption of the % symbol.
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Jurisdictional Note
Per cent as a unit of measurement is universal across legal systems, but the legal consequences attached to specific percentage thresholds vary significantly by jurisdiction. Interest rate limits, usury ceilings, voting thresholds, and regulatory trigger points are all jurisdiction-specific. Researchers should not treat a percentage figure in isolation — its legal effect depends entirely on the governing statute or instrument.
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