An Area Code for the Birmingham, Alabama Area.

Also Means Birmingham, Alabama.

1.) 205 (Two -oh-five) is a term used when a subject is introduced as if new, yet everyone else has heard of it previously.
2.) Used like a shorthand response when a nOob posts an image or notable news to a message board or email list in which all participants have beaten the subject like a dead mulie.

205 is slang for black people.
This bodybuilder weighed 205 pounds, black people are generally muscular and more strong, therefore we call them 205, its a compliment I believe.

The numbers in Jimin and Namjoon's clothes and the timestamp in BTS' No More Dream Official MV where it glitches Jimin's face and scared the heck out of Armys.