Top grade woman (= 10 out of 10). From the movie '10', featuring Dudley Moore and Bo Derek.

Noun: a friend who is usually only called upon by a friend when a more primary/prominent friend is unavailable.

Taken from the term “second string” in an athletic competition situation. In football, if the star quarterback gets injured during a play, the second string is called off the bench to replace him/her. A “Second String Friend” is essentially benched until needed, if ever.

Synonyms: Plan B, Second Choice, Secondary Friend, Benched Until Needed

Quick and somewhat widely used word to claim someone of the oppisite sex is of the top percentile in looks, sexual skills and/or personality.

Means two in the binary (base-2) numeral system.
Means three in the ternary (base-3) numeral system.
Means four in the quaternary (base-4) numeral system.
And so on...

One exception is the unary (base-1) system, where 10 probably means "WTF? ^^".

It's a number you idiot what are you doing searching this up you know very well what a number is.

(1)1, 2, 3, 4, 5, 6, 7, 8, 9, 10!
(2)2 in binary

The number that represents a couple that consists of one very slender partner and another very obese partner. Seeing the two side by side is like seeing the number 10.