DCHP-2

backbench back bench, back-bench DCHP-2 (July 2016)

• 1 n. — Politics

  a seat occupied by a member of a legislative assembly who is neither a cabinet member nor an opposition critic.

  Type: 2. Preservation — Backbench is a preservation from British English, where the term has been used since the early 19th century in the British parliamentary system. As demonstrated in Chart 1, the term is also in use in other former British colonies. Backbench is found in the US, for instance, sometimes in reference to new Congress members (see Gage-5, s.v. "back-bench" [2]).
  See also COD-2, s.v. "backbench" (1), which is marked "Cdn, Brit., Austral. & NZ", and ITP Nelson, s.v. "back-bench" (1), which is marked "Chiefly Canadian & British".

  See also: backbencher  

• 2 n. & adj. — Politics

  the group of people who occupy the backbench; often in a compound, as in back bench member.

  Type: 3. Semantic Change — Meaning 2 is, in contrast to meaning 1, probably not a preservation from British English, as attestations in this attributive or compound form appear later in the London Times (1909) than in Canadian sources (see the 1879 quotation). There is some reason to cautiously suggest, in line with other 19th century evidence (e.g. Dollinger 2015a: 33-38, Brinton 2015: 31-32), that the attributive use is a North American, perhaps even a Canadian, innovation. A Type 3 - Semantic Change is plausible, from its nominal to adjectival meanings; see e.g. the 19th century quotes, as well as its metonymical use (i.e. the backbench stands for the members sitting on it, see, e.g., the 1993 quotation).
  See also COD-2, s.v. "backbench" (3), which is marked "Cdn, Brit., Austral., & NZ".