blackthorn UK /ˈblækˌθɔːn/US /ˈblækˌθɔɹn/ noun2 •A large shrub or small tree, Prunus spinosa, that is native to Europe, western Asia, and north Africa. It has a dark bark and bears thorns. •A stick or staff taken from this tree.Cut a stout blackthorn to banish ghost and goblins. — 1964 formsblackthorns