late 14c., from Old French induracion "hardness, obstinacy" (14c.) or directly from Medieval Latin indurationem (nominative induratio) "hardness (especially of the heart)," noun of action from indurare (see endure).
induration in·du·ra·tion (ĭn'də-rā'shən, -dyə-)
The hardening of a normally soft tissue or organ, especially the skin, because of inflammation, infiltration of a neoplasm, or an accumulation of blood.
A focus or region of abnormally hardened tissue.