Definition
An error in the computation or reckoning of time. In legal contexts, metachronism refers to a mistake in which a date, period, or chronological sequence is incorrectly calculated or assigned — placing an event, deadline, or legal act at a time other than its actual or proper one. The term appears most often in older pleading and procedure contexts, where precise dating of instruments, acts, and legal events carried formal consequence.
Common Language
Modern common usage (Wiktionary): An error in chronological ordering in which a character or an event is placed at too late a time.
Historical common usage (Webster's 1913): An error committed in chronology by placing an event after its real time.
The common definitions are narrower than the legal one in one important respect: both Wiktionary and Webster's treat metachronism as specifically about placing an event too late. The legal definition, as captured in Black's, is broader — an error in computation of time generally, without confining the mistake to a particular direction. A legal metachronism may involve miscalculation forward or backward, or a simple arithmetic error in counting days.
Common Confusion
Metachronism should not be confused with anachronism. An anachronism is a general term for anything out of its proper historical time (commonly used to mean something placed too early). Metachronism, in its strict sense, refers specifically to a computational or chronological error — a mistake in reckoning — rather than a conceptual or contextual displacement in time. In practice, older legal writers sometimes used the terms interchangeably, but Black's reserves metachronism for computational error in legal proceedings and instruments.
Why It Matters in Research
Metachronism is a rare term in the active legal vocabulary and will appear almost exclusively in older treatises, pleading manuals, and common law sources. Researchers are most likely to encounter it when working through historical materials on:
Pleading defects. Under common law pleading, a defective date in a declaration or indictment could be assigned as error. Writers categorizing those defects sometimes used metachronism as a term of art alongside related Latin and English pleading terminology. Understanding the term is necessary to parse those passages correctly.
Statute of limitations and laches analysis. Historical discussions of time-bar defenses occasionally invoke metachronism when describing errors in computing when a cause of action accrued or when a limitations period expired. A researcher tracing the development of limitations doctrine in equity or common law courts may need to recognize the term to follow the argument.
Corpus search traps. Because metachronism is uncommon and its spelling varies in historical transcription (metachronisme, metachronisum, and other corruptions appear in digitized texts), full-text searches across historical legal databases may return incomplete results. Researchers should supplement keyword searches with contextual reading of surrounding pleading-defect discussions.
The term carries no modern statutory definition and does not appear in contemporary procedural codes. Its value is almost entirely interpretive — useful for reading older sources accurately, not for applying current law.
Historical Dictionary Support
Black's Law Dictionary (1st and 2nd editions) are in full agreement: metachronism is defined identically in both as "an error in computation of time." Neither edition elaborates, offers illustrative examples, or connects the term to specific procedural consequences. This brevity reflects the term's status as borrowed vocabulary — a learned word imported from classical chronology into legal usage without significant independent doctrinal development.
Webster's 1913 adds a nuance absent from both editions of Black's: the error is specifically one of placing an event after its real time. This directional precision is worth noting because it tracks the Greek and Latin etymological sense of the word, suggesting post-dating rather than a general miscalculation. Black's apparent broadening of the term to cover any computational error — without specifying direction — may reflect practical legal usage, where the consequences of misdating an instrument or deadline did not typically depend on whether the error ran forward or backward.
No historical dictionary source connects metachronism to a specific body of case law or procedural rule. Researchers should treat it as descriptive vocabulary used by pleading writers to categorize a class of defect, rather than as a term carrying its own distinct legal test or remedy.