Cover-up term for bisexual.
This is because of the periodic table of the chemical elements (chemistry): The 83rd element is Bismuth, which is abbreviated with "Bi".
(67 42 = Homo)

Hetrosexual Oral Sex. Think about it - "69" would only work for M/M or F/F sex...

Stupid answer to a stupid question. It can be used when a student in class is too slow to write something down and has to ask the others to repeat the last part all the time.

After a while you'll get annoyed and you just answer "83!".

It can also be used when someone asks a question of which he could have found the answer if he just thought a little.

anal sex (think on the 8 as an ass & the 3 as wang)

A person that is bisexual.

The rate butthurt Murphy gave Samantha went they stopped dating. He tried, Samantha laughed...

Hiphop guys (2Faces, BIC, Canox, Ben, T-Mo, ..) from Quebec southside. Their name come from the two first numbers in local phone numbers (83)x-xxxx