least-cost

The compound adjective 'least-cost' is a modern analytical formation, combining two native English elements with transparent meanings. 'Least' originates from the Old English superlative 'læst', itself derived from the Proto-Germanic comparative system for expressing minimal degree. 'Cost' entered English via Anglo-Norman and Old French from the Latin verb 'constare', which literally meant 'to stand together' but evolved in Medieval Latin to signify a fixed price. The compound's logic is purely syntactic and literal, directly merging the concept of the 'smallest' ('least') with that of 'expenditure' ('cost') to create a term specifically used in economics, engineering, and planning to describe the option involving minimal financial outlay.

Structure: least (smallest) + cost (price, expenditure) - least: From Old English 'læst', superlative form of 'læssa' (less). Origin: Proto-Germanic. Role: Adjective modifier indicating the minimum degree. - cost: From Old French 'cost', from Latin 'constare' ('to stand at, to cost'). Origin: Latin via Old French. Role: Noun root denoting expense or price.