Quieten
Quieten is a verb used chiefly in British English that means to make or become quiet, either by reducing noise or by calming someone or something. It can be transitive, as in to quieten someone or something, or intransitive, meaning to become quiet. In everyday usage, forms include quieten, quietens, quietened, and quietening. In American English, the more common verbs are quiet or quiet down; past tense is usually quieted, and present tense quiets.
Etymology and usage notes: Quieten derives from the adjective quiet, with the suffix -en added to form