- sole (n.1)
- "bottom of the foot," early 14c., from Old French sole, from Latin solea "sandal, bottom of a shoe," from solum "bottom, ground, soil," of unknown origin. The verb meaning "to provide with a sole" is recorded from 1560s.
- sole (adj.)
- "single," late 14c., from Old French soul (fem. soule), from Latin solus "alone," of unknown origin, perhaps related to se "oneself," from PIE reflexive root *swo- (see so).
- sole (n.2)
- "flatfish," mid-13c., from Old French sole, from Latin solea "a kind of flatfish," originally "sandal" (see sole (n.1)), so called from resemblance of the fish to a sandal.