the rear, back, or backside of something / the rearward or backward direction / the portion of a palace where a queen or other female imperial consort lives

prefixing element in kanji compounds, adding a meaning of later, after, following, rearward

later, afterwards, some time after the present

after

later, afterwards, some time after the present

(後 "spatially behind") to depart from; to leave / (後 "temporally later") to put off something, to be dealt with later

facing / opposite

backward compatibility

spectroscopy (scientific study of spectra)

(military) anti-aircraft gun, anti-aircraft cannon