a hard and sharp-pointed projection from a woody stem; usually, a branch so transformed; a spine.-any shrub or small tree which bears thorns; especially, any species of the genus crataegus, as the hawthorn, whitethorn, cockspur thorn.-fig.: that which pricks or annoys as a thorn; anything troublesome; trouble; care.-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.-to prick, as with a thorn.