tauto-

1.
a combining form meaning “same,” used in the formation of compound words:
tautomerism.
Origin
< Greek, combining form of tautó, contraction of tò autó the same
British Dictionary definitions for tauto-

tauto-

combining form
1.
identical or same: tautology, tautonym
Word Origin
from Greek tauto, from to auto
tauto- in Medicine

tauto- or taut-
pref.
Same; identical: tautomeric.