Where does “mēnstruus” come from?
mēnstruus (Latin) comes from Latin bimestris, from Latin mēnsis, from Proto-Italic mēnsis, from Proto-Italic mēns, from Proto-Indo-European mḗh₁n̥s, from Proto-Indo-European meh₁- — to measure.
Ancestry of “mēnstruus”, step by step