induration of the arteries

NOUN
26 LETTERS · STARTS WITH I

induration of the arteries is a valid 26-letter word worth 30 points in Scrabble and 32 points in Words with Friends.

SCRABBLE WORDS WITH FRIENDS
I1N1D2U1R1A1T1I1O1N1O1F4T1H4E1A1R1T1E1R1I1E1S1
1 + 1 + 2 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 0 + 1 + 4 + 0 + 1 + 4 + 1 + 0 + 1 + 1 + 1 + 1 + 1 + 1 + 1 + 1 =30 PTS
DOUBLE WORD → 60TRIPLE WORD → 90
MEANING

What does induration of the arteries mean?