In linguistics, a calque is a form of borrowing where it is not so much the word that is borrowed as the meaning.
For example, the Greek 'κοσμος' "order, ornament", (whence cosmetics) came to mean "the world" (whence cosmos). Latin 'mundus', "women's cosmetics" apparently calqued this meaning, and also came to mean "world" (whence mundane or Spanish 'mundo'). (At least so my dictionary tells me.)
It is not necessarily loan translation; loan translation is a kind of calque. In loan translation a compound or phrase is directly translated into a new native compound or phrase (as with Übermensch and superman). Other calques add a new meaning to an existing word; something like idiom translation. If we calqued Spanish "esperar" (to hope, or to wait) onto English "hope", that means we have added the meaning "wait" to the word "hope" that wasn't there before. | 
