What It Scores
BI is a valid word in the tournament list this site uses. Tile values only, before any premium square: 4 in Scrabble and 5 in Words With Friends. The letters break down as B3 I1.
Longer Words Containing BI
BI appears inside each of these, which is what makes it worth knowing as a hook.
Next: the Word Unscrambler for any letters at all, and the two and three letter lists. Full entry and definition at Merriam-Webster.