proto-

combining form

variants or before a vowel prot-

1

a

: first in time

protohistory

b

: beginning : giving rise to

protoplanet

2

: parent substance of a (specified) substance

protactinium

3

: first formed : primary

protoxylem

4

capitalized : relating to or constituting the recorded or assumed language that is ancestral to a language or to a group of related languages or dialects

Proto-Indo-European

Word History

Etymology

Greek prōt-, prōto-, from prōtos; akin to Greek pro before — more at for