Couple.

[Paul McFedries]

And another thing...

Since the informal couple (sans of) usage means "two or a few," could it
also be related to the expression "couple, two, three," as seen in the
following cite from something called "Denver Westword":

"He admitted to having had sex with her a 'couple, two, three times,' the
first in August 1998."

This would also seem to mean "two or a few," so perhaps in addition to
Dennis' phonological argument, the informal couple is a shortening of this
longer and puzzlingly redundant phrase. This would require that "couple,
two, three" have had widespread usage in the past, so perhaps I'm making
things too complicated again.

Paul