prot-
Multiple Entries:prot- proto-
Concise Oxford English Dictionary © 2008 Oxford University Press:
prot-
▶combining form variant spelling of proto- before a vowel (as in protanopia).
Concise Oxford English Dictionary © 2008 Oxford University Press:
proto- /ˈprəʊtəʊ/ (usu. prot- before a vowel)
▶combining form original; primitive: prototype.
■ first; anterior; relating to a precursor: protozoon.
– origin from Gk prōtos ‘first’.
'prot-' also found in these Oxford entries:

