Sort of off-topic but only partly because the original article asked for origins of terms, exit has a fascinating etymology. Unlike most words, "exit" is a loan word in a conjugated form. It comes from the third person singular indicative of a Latin verb, exire ("to go out"). In other words, it means, in Latin "He or she leaves." Most loan words come from some sort of base form, which tells you there is an interesting backstory here.

From what I understand it entered into English as a stage direction, but by the 16th century it had become a noun referring to a doorway for leaving.