'Proto-' definitions:

Definition of 'Proto-'

From: GCIDE
  • Proto- \Pro"to-\ [Gr. prw^tos first, a superl. fr. pro` before. See Pro-.]
  • 1. A combining form prefix signifying first, primary, primordial; as, protomartyr, the first martyr; protomorphic, primitive in form; protoplast, a primordial organism; prototype, protozoan. [1913 Webster]
  • 2. (Chem.) (a) Denoting the first or lowest of a series, or the one having the smallest amount of the element to the name of which it is prefixed; as protoxide, protochloride, etc. (b) Sometimes used as equivalent to mono-, as indicating that the compound has but one atom of the element to the name of which it is prefixed. Also used adjectively. [1913 Webster]