"application" (of one thing to another), mid-15c., originally in grammatical sense, from Latin appositionem (nominative appositio), noun of action from past participle stem of apponere "to put to" (see apposite). General sense is from 1540s.
apposition ap·po·si·tion (āp'ə-zĭsh'ən)
The putting in contact of two parts or substances.
The condition of being placed or fitted together.
The growth of successive layers of a cell wall.