An analogy is (1) a similarity between two things that are otherwise dissimilar, and (2) a comparison based on such a similarity. An analogue (now usually spelled analog in North America) is something that can be likened to something else by analogy.
The words are closely related, sharing a root in a Greek adjective meaning proportionate, and they both came to English from French, but at different times. Analogy descends from the Middle English analogie, which came from Old French and was commonly used in contexts related to mathematics and grammar before gaining broader use with the modern spelling. The newer analogue came directly from French around 1800, bearing the word’s French sense and spelling. The newer spelling, analog, developed in the U.S. around the early 20th century and is now preferred in the U.S. and to a lesser extent in Canada.
Boehner hails from the same part of Ohio and aspires to be remembered as the working-class analog to the patrician Longworth. [Slate]
Yet I fail to see how Leunig’s Israel-Nazi analogy contributes anything to promoting a peaceful resolution to the conflict. [The Age]
The annual international beauty contest, an analogue to Miss World which emphasises environmental issues, is being held in the Philippines. [Telegraph]
The analogy with Iraq is troubling for the US and British governments. [Independent]
While animal research has value in identifying potential items of interest, it cannot serve as a perfect analog to human experience. [Consumer Freedom]
Earth’s orbit was different during the last warm period, bringing more sunshine to the Arctic and complicating the analogy with today. [New York Times]