I think its got to be a 'formal First Contact'.
Say Kirk with the Gorn. Technically the people on the Starbase that the Gorns wiped out were the first to contact the Gorns. Charlie X was the first to contact the Thasians too.
I think 'First Contact' must be where the
represenatives of one species have formal acknowledged interaction with the representatives of another species in either a friendly or unfriendly manner