刺,螫刺
Aculeus \A*cu"le*us\, n.; pl. {Aculei}. [L., dim. of acus needle.] 1. (Bot.) A prickle growing on the bark, as in some brambles and roses. --Lindley. 2. (Zo["o]l.) A sting.
aculeus n 1: a stiff sharp-pointed plant process 2: a sharp-pointed process especially a sting of a hymenopterous insect