Du`o*dec"i*mal (?), a. [L. duodecim twelve. See Dozen.] Proceeding in computation by twelves; expressed in the scale of twelves. -- Du`o*dec"i*mal*ly, adv.

Du`o*dec"i*mal, n. 1. A twelfth part; as, the duodecimals of an inch.

2. pl. (Arch.) A system of numbers, whose denominations rise in a scale of twelves, as of feet and inches. The system is used chiefly by artificers in computing the superficial and solid contents of their work.

• (arithmetic) Of a number, expressed in duodecimal.
  
• (arithmetic) A number system that uses 12 as its base.