1. Of little significance or value.
2. Ordinary; commonplace.
3. Concerned with or involving trivia.
4. Biology Relating to or designating a species; specific.
5. Mathematics
   1. Of, relating to, or being the solution of an equation in which every variable is equal to zero.
   2. Of, relating to, or being the simplest possible case; self-evident.

Synonyms: These adjectives all apply to what is small and unimportant. Trivial and trifling refer to what is so insignificant as to be utterly commonplace or unremarkable: "I think all Christians . . . agree in the essential articles, and that their differences are trivial" (Samuel Johnson). "I regret the trifling narrow contracted education of the females of my own country" (Abigail Adams).
Paltry describes what falls so far short of what is required or desired that it arouses contempt: "He . . . considered the prize too paltry for the lives it must cost" (John Lothrop Motley).
Petty can refer to what is of minor or secondary significance or size: "Our knights are limited to petty enterprises" (Sir Walter Scott).
What is picayune is of negligible value or importance: a picayune infraction of the law.

Word History: The word trivial entered Middle English with senses quite different from its most common contemporary ones. We find in a work from 1432-50 mention of the "arte trivialle," an allusion to the three liberal arts that made up the trivium, the lower division of the seven liberal arts taught in medieval universities—grammar, rhetoric, and logic. The history of trivial goes back to the Latin word trivium, formed from the prefix tri-, "three," and via, "road." Trivium thus meant "the meeting place of three roads, especially as a place of public resort." The publicness of such a place also gave the word a pejorative sense that we express in the phrase the gutter, as in "His manners were formed in the gutter." The Latin adjective triviālis, derived from trivium, thus meant "appropriate to the street corner, commonplace, vulgar." Trivial is first recorded in English with a sense identical to that of triviālis in 1589. Shortly after that trivial is recorded in the sense most familiar to us, "of little importance or significance," making it a word now used of things less weighty than grammar, rhetoric, and logic.