Tauto is defined as the same.
An example of tauto used as a prefix is the word tautologous, meaning repeating the same thing.
the same: tautology
Origin of tauto-Classical Greek from tauto from to auto, the same
Same; identical: tautomerism.
Origin of tauto-Greek from tauto the same contraction of to auto to the ; see to- in Indo-European roots. auto neuter of autos same, self