requirement n.

late 14c., requeren, "to ask (someone) a question, inquire," a sense now obsolete, from Old French requerre, requerir "seek, procure; beg, ask, petition; demand," from Vulgar Latin *requaerere, from Latin requirere "seek to know, ask, ask for (something needed)," from re-, here perhaps meaning "repeatedly" (see re-), + quaerere "ask, seek" (see query (v.)). In some later English senses probably directly from Latin.

Still in 16c.-17c. commonly "to ask or request (to have or do something)," but this original sense of the word has been taken over by request (v.).

Also from late 14c. as "to stand in need of, want; to need for some end or purpose." The sense of "demand that (someone) do (something)" is from 1751, via the notion of "to ask for imperatively, or as a right" (late 14c.). The meaning "demand as necessary or essential on general principles" is from early 15c. Related: Required; requiring.

common suffix of Latin origin forming nouns, originally from French and representing Latin -mentum, which was added to verb stems to make nouns indicating the result or product of the action of the verb or the means or instrument of the action. In Vulgar Latin and Old French it came to be used as a formative in nouns of action. French inserts an -e- between the verbal root and the suffix (as in commenc-e-ment from commenc-er; with verbs in ir, -i- is inserted instead (as in sent-i-ment from sentir).

Used with English verb stems from 16c. (for example amazement, betterment, merriment, the last of which also illustrates the habit of turning -y to -i- before this suffix).

The stems to which -ment is normally appended are those of verbs; freaks like oddment & funniment should not be made a precedent of; they are themselves due to misconception of merriment, which is not from the adjective, but from an obsolete verb merry to rejoice. [Fowler]