“thorn,” “spiny projection,” “thorny plant” — morphological combining form denoting thorn-like or spiculated structures
The word entered English in the 1550s as acanthus (noun), borrowed from French acanthe, from Late Latin acanthus, from Greek ἀκάνθη (akanthē) — literally “thorn.” The medical adjective acanthous appeared in the 1840s, and the noun acanthosis in the 1870s. The root akanthē (“thorn”) connects acanth- to the entire spine and projection roots: acanthosis (acanth- + -osis → thorn-like thickening of the skin), acanthocyte (acanth- + kytos → thorn-shaped red blood cell), and acanthoma (acanth- + -oma → benign epidermal growth with thorn-like projections). The combining formacanth- is productive in dermatology, hematology, and histology: e.g., acanthosis nigricans, acanthoblastic, acanthocele, and acantholysis.