indurate comes from Latin induratus, past participle of indurare ('to harden'), from in- (intensive) + durare ('to harden, last'), from durus ('hard'). Morphologically, the prefixed shape matters: the initial element belongs to the recorded formation and helps explain the modern form's surface analysis. In present English, the verb sense is "to make or become hard, or to harden in feeling", so the historical development ends in a clearly identifiable modern dictionary use. The same base also appears in related forms such as durable, duration, endure, and durance, and in derivatives such as induration and indurative. Its semantic neighborhood includes harden, solidify, stiffen, and callous, which helps locate the modern sense without adding a separate etymological claim. The named historical forms include Latin indurare and Latin durus.