interchangeable bond

20 LETTERS · STARTS WITH I

interchangeable bond is a valid 20-letter word worth 30 points in Scrabble and 37 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS

I1N1T1E1R1C3H4A1N1G2E1A1B3L1E1B3O1N1D2

1 + 1 + 1 + 1 + 1 + 3 + 4 + 1 + 1 + 2 + 1 + 1 + 3 + 1 + 1 + 0 + 3 + 1 + 1 + 2 =30 PTS

DOUBLE WORD → 60TRIPLE WORD → 90

MEANING

What does interchangeable bond mean?