first of all

ADVERB
12 LETTERS · STARTS WITH F

first of all is a valid 12-letter word worth 16 points in Scrabble and 18 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
F4I1R1S1T1O1F4A1L1L1
4 + 1 + 1 + 1 + 1 + 0 + 1 + 4 + 0 + 1 + 1 + 1 =16 PTS
DOUBLE WORD → 32TRIPLE WORD → 48
MEANING

What does first of all mean?

ADVERB · 1 SENSE
1

Before anything else.