[...] strictly speaking, words are "inflected" (i.e. they vary their "form") according to their "accidence" (from the Latin "accidentia", "accidental properties").
- Lyons (2004), a pag.18

The standard reference grammars of Greek and Latin, and the grammars of modern languages which are based on classical principles, are generally divided into three section, not two: namely, into inflexion (or "accidence"), derivation (or "word-formation"), and syntax.
- Lyons (2004), a pag.15