that is to say

ADVERB
14 LETTERS · STARTS WITH T

that is to say is a valid 14-letter word worth 17 points in Scrabble and 15 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
T1H4A1T1I1S1T1O1S1A1Y4
1 + 4 + 1 + 1 + 0 + 1 + 1 + 0 + 1 + 1 + 0 + 1 + 1 + 4 =17 PTS
DOUBLE WORD → 34TRIPLE WORD → 51
MEANING

What does that is to say mean?

ADVERB · 1 SENSE
1

As follows.