"Thorn" is a word in ENGLISH

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.

Any shrub or small tree which bears thorns; especially, any
species of the genus Crataegus, as the hawthorn, whitethorn, cockspur
thorn.

To prick, as with a thorn.

Fig.: That which pricks or annoys as a thorn; anything
troublesome; trouble; care.

A hard and sharp-pointed projection from a woody stem;
usually, a branch so transformed; a spine.