The first definition of “Revelation” according to Merriam-Webster is 1a: an act of revealing or communicating divine truth; b: something that is revealed by God to humans.
In Bahá’u’lláh’s own words, it came as a torrent:
“In those infrequent moments of slumber I felt as if something flowed from the crown of My head over My breast, even as a mighty torrent that precipitateth itself upon the earth from the summit of a lofty mountain. Every limb of My body would, as a result, be set afire. At such moments My tongue recited what no man could bear to hear.”
(God Passes By, pg. 101)
Over a span of nearly 40 years, a series of scribes attended Bahá’u’lláh to record what was revealed through Him; as a result we have over one hundred volumes of scripture, much of it reviewed and validated by Himself. Even today it continues to be translated in many languages and made available all over the world.