Stress in Compounds

A compound is composed of more than one root morpheme (mostly two free morphemes) but functions like a single word in syntactic and semantic terms. The practice in the written language is not consistent; a compound can be written as a single word (e.g. blueprint), or with a hyphen in between (e.g. fail-safe), or with a space between the elements (e.g. flower girl). Although there are no consistent rules of choice among these, there seems to be a tendency for the ones with a primary stress on the first element to be written as one word or with a hyphen in between, and the ones that receive the main stress on the second element to be written with a space in between.