This word has two primary meanings: "a wearing out, collapse" and "analysis, decomposition": "Millie suffered a breakdown following the accident." "The factory was closed because of a breakdown in machinery." "The treasurer made a careful breakdown of income and expenses." In the second of its meanings, breakdown is overused and loosely used. Instead of using this word vaguely, occasionally say analysis, classification, examination, or itemization. See also analysis.
Dictionary of problem words and expressions. Harry Shaw. 1975.