English
gerospan
From gero- + span, modelled after lifespan.
Formed from gero- + span
Proto-Indo-European *(s)pend- ‘to stretch’
Proto-Germanic *spannō ‘span, handbreadth’
Old English spann
Middle English spanne ‘a span’
English span
Today it means
noun The length of time in one's life where one is geriatric.
Language periods are conventional ranges, not dates for this word.
Etymograph / gerospan