moon
Earth's natural satellite; the celestial body visible at night.
Etymology
From Old English mōna, from Proto-Germanic *mēnō, from PIE *méh₁n̥s, which also meant "month" — because months were originally measured by lunar cycles. The root is connected to PIE *meh₁- "to measure." The moon was literally "the measurer."
The Journey: *méh₁n̥s → moon
*méh₁n̥s
*mēnō
mōna
mone
moon
Cognates Across Languages
These words in other languages descend from the same PIE root *méh₁n̥s. They are not borrowings but independent inheritances from a common ancestor.
| Language | Word |
|---|---|
| Greek | mḗn (month) |
| Latin | mēnsis (month) |
| Sanskrit | mā́s |
| Old Irish | mí (month) |
| Lithuanian | mėnuo |
| Old Church Slavonic | měsęcĭ |
Did You Know?
The words "moon," "month," "measure," and "menstrual" all trace back to the same PIE root *meh₁- "to measure." Ancient peoples measured time by the moon — the month was literally one moon-cycle.
This word descends from the Proto-Indo-European root *méh₁n̥s. See the full root page for descendant trees, sound law references, and scholarly discussion.