-ole

Etymology 1
Arbitrary variant of, now used to distinguish between specific cases.

Derived terms

 * arsole, azole (triazole, tetrazole, pentazole; oxazole, thiazole; isoxazole, isothiazole), bismole, borole, imidazole, indole, oxole, phosphole, pyrazole, pyrrole, silole, stannole, stibole, thiole

Etymology 2
From Latin -olus, from -lus.

Suffix

 * 1) A diminutive suffix referring to small parts of organisms or their cells.

Etymology
. Many words ending in were borrowed with the suffix already present.