A nickname or shortened form of the name Isaac, or informal term for an ice axe used in mountaineering.
From the Hebrew name Yitzchak meaning 'he will laugh.' As a nickname, it became popular in English-speaking countries by the 19th century, especially as a standalone diminutive.
President Dwight D. Eisenhower was famously called 'Ike,' making this one of the most famous nicknames in American history and helping cement it as a word in its own right.
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