Etymology Dictionary

ALOUD,  loudly.  (E.)   Chiefly in the phrase 'to cry aloud.'   M.E. 'to crye aloude;' Chaucer, Troilus, ii. 401.   By analogy with abed, asleep, afoot, &c., the prefix must be on, from which it follows that loud is a substantive, not an adjective.   β. It stands, then, for E. E. on lude, where lude is the dative case of a substantive signifying 'din,' 'loud sound;' cf. 'mid muchelen lude,' later text 'mid mochelere loude,' i.e. with a great 'loud,' with a great din; Layamon, l. 2591.—A.S. hlyd, sb. a din; closely related to adj. hlúd, loud. + Icel. hljóð, sb. a sound. + Dan. lyd, a sound. + Swed. ljud, a sound. + Du. luid, a sound, the tenor of a thing. + G. laut, a sound, tone.   ¶ Thus Eng. is the only one of these languages which no longer uses loud as a substantive.   See Loud.