idioms - Why don't we pluralize "foot" in measurements?
For example, to answer the question, "How tall are you?" valid answers include: Five feet . Five foot three. Five feet , three inches. Why the discrepancy between feet and foot , seemingly only in the second case. This question is inspired by this question: "Forty foot" or "forty feet"? edit: I do not believe the answer to this is related to the other question. The explanation for the other question is because of how adjective modifiers work. My question is a very different case, unrelated to adjectives. My observation is that I am asking about a particular exception case which applies only when "foot" is followed by a number which is assumed to be inches. That's extremely specific, and I doubt that the etymology has any relation to why we leave adjective modifiers singular. Answer I think it's "idiomatic by association". ( this NGram should be enough to at least prove a trend) There's long-standing 'idiomatic'...