Strong’s Greek
G5039 — tekmerion
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
τεκμήριον
tekmerion — pronounced tek-may'-ree-on
neuter of a presumed derivative of tekmar (a goal or fixed limit); a token (as defining a fact), i.e. criterion of certainty:--infallible proof.
1 occurrence in the KJV.
Acts 1:3
To whom also he shewed himself alive after his passion by many infallible proofs, being seen of them forty days, and speaking of the things pertaining to the kingdom of God: