Entry 2 senses Webster, 1913 Acanthaceous · Ac·an·tha·ceous · IPA /ˌæk.n̩ˈθeɪ.ʃəs/ 01 a. Armed with prickles, as a plant. 1. Armed with prickles, as a plant. 2. Of, pertaining to, or resembling, the family of plants of which the acanthus is the type.(Bot.)