induration (n.)

late 14c., "to undergo or suffer" (especially without breaking); also "to continue in existence," from Old French endurer (12c.) "make hard, harden; bear, tolerate; keep up, maintain," from Latin indurare "make hard," in Late Latin "harden (the heart) against," from in- (from PIE root *en "in") + durare "to harden," from durus "hard," from PIE *dru-ro-, suffixed variant form of root *deru- "be firm, solid, steadfast."

Replaced the important Old English verb dreogan (past tense dreag, past participle drogen), which survives in dialectal dree. Related: Endured; endures.