late 14c., "of or manifesting life," from Latin vitalis "of or belonging to life," from vita "life," related to vivere "to live," from PIE root *gwei- "to live." The sense of "necessary or important" is from 1610s, via the notion of "essential to life" (late 15c.). Vital capacity recorded from 1852. Related: Vitally.

Latin, "weariness of life; a deep disgust with life tempting one to suicide."

1847, "mental affection or derangement," Modern Latin, from Greek psykhē "mind, life, soul" (see psyche) + -osis "abnormal condition." Greek psykhosis meant "a giving of life; animation; principle of life."

"consisting of or pertaining to facts, not fanciful or ideal," 1712, from the noun phrase matter of fact "reality as distinguished from what is fanciful or hypothetical, truth attested by direct observation or authentic testimony," which is originally a legal term (1570s, translating Latin res facti), "that which is fact or alleged fact; that portion of an inquiry concerned with the truth or falsehood of alleged facts, subject of discussion belonging to the realm of fact" (as distinguished from matter of inference, opinion, law, etc.). See matter (n.) + fact.

The meaning "prosaic, unimaginative, adhering to facts" is from 1787. Related: Matter-of-factly; matter-of-factness. German Tatsache is said to be a loan-translation of the English word.

In law, that which is fact or alleged as fact; in contradistinction to matter of law, which consists in the resulting relations, rights, and obligations which the law establishes in view of given facts. Thus, the questions whether a man executed a contract, and whether he was intoxicated at the time, relate to matters of fact; whether, if so, he is bound by the contract, and what the instrument means, are matters of law. [Century Dictionary]

also re-appraisal, "reassessment in light of new facts," by 1846, from re- "back, again" + appraisal, or else a noun formed to go with reappraise (v.).

1743, French, "to the point, to the matter under discussion," literally "to the fact," from au "to the" (see au) + fait "fact" (see feat). Used in French with sense of "acquainted with the facts, expert, fully skilled."

Old English liflic "living, existing," literally "life-like;" from life + -ly (2). The main modern sense of "active, energetic" developed by early 13c., from notion "full of life." For "full of life, vigorous," Old English had liffæst. The adverb is Old English liflice "vitally," from the adjective. Related: Liveliness.

1828, from French viable "capable of life" (1530s), from vie "life" (from Latin vita "life," from PIE root *gwei- "to live") + -able. Originally of newborn infants; generalized sense is first recorded 1848. Related: Viably.

1590s, from Latin vitalitatem (nominative vitalitas) "vital force, life," from vitalis "pertaining to life" (see vital).

word-forming element, especially in scientific compounds, meaning "life, life and," or "biology, biology and," or "biological, of or pertaining to living organisms or their constituents," from Greek bios "one's life, course or way of living, lifetime" (as opposed to zoe "animal life, organic life"), from PIE root *gwei- "to live."

The correct usage is that in biography, but since c. 1800 in modern science it has been extended to mean "organic life," as zoo-, the better choice, is restricted in modern use to animal, as opposed to plant, life. Both are from the same PIE root. Compare biology.