An "Acronym" for "Brooklyn". Widely used by people who feel need to prove they're from there. Or just lazy people, and some stupid people. It is sometimes used on MSN Messenger and various cell phones (Virgin Mobile, Fido ect.), txting back and forth. Maybe even spraypainted on buildings, and scribbled in bathroom stalls.
Some of us find "Bklyn" an absolutely horrendous and disgusting abbreviation for "Brooklyn". Annoys me more than "the big apple" does.
Pajama casual is a term used when working from home and preparing for a video conference. All business above the waist and your pajama pants down below.