'cementum' definitions:

Definition of 'cementum'

noun

A specialized bony substance covering the root of a tooth [syn: cementum, cement]

From: GCIDE

Cement \Ce*ment"\ (s[e^]*m[e^]nt" or s[e^]m"[e^]nt), n. [OF. cement, ciment, F. ciment, fr. L. caementum a rough, unhewn stone, pieces or chips of marble, from which mortar was made, contr. fr. caedimentum, fr. caedere to cut, prob. akin to scindere to cleave, and to E. shed, v. t.]
1. Any substance used for making bodies adhere to each other, as mortar, glue, etc. [1913 Webster]
2. A kind of calcined limestone, or a calcined mixture of clay and lime, for making mortar which will harden under water. [1913 Webster]
3. The powder used in cementation. See Cementation, n., 2. [1913 Webster]
4. Bond of union; that which unites firmly, as persons in friendship, or men in society. "The cement of our love." [1913 Webster]
5. (Anat.) The layer of bone investing the root and neck of a tooth; -- called also cementum. [1913 Webster]
Hydraulic cement. See under Hydraulic. [1913 Webster]