English
fillup
From fill + up.
Proto-Indo-European *pleh₁- ‘to fill’
…
Proto-Germanic *fullijaną ‘to make full’
Proto-West Germanic *fullijan ‘to fill’
Old English fyllan ‘to fill’
Middle English fillen ‘to fill up’
English fill
Proto-Germanic *upp ‘up’
Proto-West Germanic *upp
Old English upp
Middle English up ‘to a vertical axis’
English up
Today it means
noun An act or process of filling up; a replenishment.
Language periods are conventional ranges, not dates for this word.
Etymograph / fillup