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

"GL" or "gl" in the manga, manhwa, manhua universe means literally girl's love. Which is a romance genre when both of the main characters are females. Often interpreted as "Yuri" for the Japanese community which means Lily. The fans of the genre are simply called Yuri enthusiast/fan. Another variant for the opposite sex is bl, which you already know it, means boy's love (I'm not into that).

Normally used is most gaming online lobbys. the term refers to GOOD LUCK. may also be used in conjunction with GG(good game) or HF(have fun)

gl is a shortened phrase of saying 'girls love.' however 'gl' can be used and shortened as 'good luck.'