Trivial, a.
Etymology: [L. trivialis, properly, that is in, or belongs to, the crossroads or public streets; hence, that may be found everywhere, common, fr. trivium a place where three roads meet, a crossroad, the public street; tri- (see Tri-) + via a way: cf. F. trivial. See Voyage.]
1. Found anywhere; common. [Obs.]
2. Ordinary; commonplace; trifling; vulgar. As a scholar, meantime, he was trivial, and incapable of labor. De Quincey.
3. Of little worth or importance; inconsiderable; trifling; petty; paltry; as, a trivial subject or affair. The trivial round, the common task. Keble.
4. Of or pertaining to the trivium. Trivial name (Nat. Hist.), the specific name.(Chem.) The common name, not describing the structure and from which the structure cannot be deduced; -- contrasted with systematic name.
1 other Webster entry under this spelling
Trivial, n.
One of the three liberal arts forming the trivium. [Obs.] Skelton. Wood.
Shades of meaning
Fernald has no entry of its own for trivial; he lists it under vain, venial.
Where he writes about it:
Aside from its technical ecclesiastical use, venial is always understood as marking some fault comparatively slight or trivial. — from venial