In obsolete|lang=en terms the difference between pair and geminy
is that
pair is (obsolete) to impair while
geminy is (obsolete) twins; a pair; a couple.
As nouns the difference between pair and geminy
is that
pair is two similar or identical things taken together; often followed by of while
geminy is (obsolete) twins; a pair; a couple.
As a verb pair
is to group into sets of two or
pair can be (obsolete) to impair.