Letters that make proto
a, o, p, r, t are letters that make 'proto'
1 possible definitions for 'proto'
Under this definition, proto is an adjective and has the following properties:
'proto(a)' can be a useage of combining form.
early is similar to proto(a).
"`proto' is a combining form in a word like `protolanguage' that refers to the hypothetical ancestor of another language or group of languages"