Etymology tree Proto-Indo-European *h₂ep Proto-Indo-European *-o Proto-Indo-European *h₂epó Proto-Indo-European *-teros Proto-Indo-European *h₂ep(o)teros Proto-Germanic *after Old English æfter Middle English after English after ▲ Old English æfter Old English æfter- Middle English after- English after- English glow English afterglow From after- + glow.