thorn /θɔːn $ θɔːrn/ BrE AmE noun
[ Language: Old English ]
1 . [countable] a sharp point that grows on the stem of a plant such as a rose
2 . [uncountable and countable] a bush or tree that has thorns:
a long, low hedge of thorns
3 . a thorn in sb’s side someone or something that annoys you or causes problems for a long period of time:
He’s been a thorn in the side of the party leadership for years.