bby
1. Abbreviation for baby. Also quite frequently might be a typo of "baby", since many people are not so lazy that they cannot type an extra letter.

2. Star Wars term used for calendar dates. Stands for "Before Battle of Yavin". Quite similar to BC in normal calendar date, which stands for "Before Christ".
1. "hey bby want to come over and have make out"

2. "Darth Vader was born 41 BBY."