O.E. ræde, geræde, from P.Gmc. *garaidijaz "arranged" (cf. O.Fris. rede, M.Du. gereit, O.H.G. reiti, M.H.G. bereite, Ger. bereit, O.N. greiðr "ready, plain," Goth. garaiþs "ordered, arranged"). Lengthened in M.E. by change of ending. The verb is recorded from early 14c. Readily is from early 14c. Ready-made first attested mid-15c.; ready-to-wear is from 1895.
Available for immediate use, as in Umbrellas at the ready, we were prepared to brave the storm. This idiom was originally a military term in which the ready denoted the position of a firearm prepared to be raised and aimed or fired.
[ First half of 1800s