The story
- Proto-Indo-European*med-
- Proto-Indo-European*meh₁-?
- Proto-Indo-European*mḗh₁n̥s
- Proto-Italic*mēns
- Proto-Italic*mēnsis
- Latinmēnsis
- Proto-Indo-European*h₂el-
- Proto-Indo-European*h₂élisder.?
- Latinmēnsuālis
- English todaymensual
Borrowed from Latin mēnsuālis (“monthly”).
Etymology from Wiktionary, CC BY-SA 4.0.