vt to prick, as with a thorn.
2. thorn ·noun fig.: that which pricks or annoys as a thorn; anything troublesome; trouble; care.
3. thorn ·noun a hard and sharp-pointed projection from a woody stem; usually, a branch so transformed; a spine.
4. thorn ·noun any shrub or small tree which bears thorns; especially, any species of the genus crataegus, as the hawthorn, whitethorn, cockspur thorn.
5. thorn ·noun the name of the anglo-saxon letter, (capital form). it was used to represent both of the sounds of english th, as in thin, then. so called because it was the initial letter of thorn, a spine.