Mid 17th century; earliest use found in Thomas Blount (1618–1679), antiquary and lexicographer. Either from reverbatory, or shortened from reverberatory.
reverbatory2
/rɪˈvəːbət(ə)ri/
adjective
Reverberatory; especially = reverberatory.
Origin
Late 16th century; earliest use found in Hugh Platt (bap. 1552, d. 1608), writer on agriculture and inventor. Apparently irregularly from reverb- + -atory, perhaps arising from misrecollection of post-classical Latin reverberatorius or reverberatory.