undern

The story

1. Proto-Indo-European · inherited from*h₁n̥ter
2. Proto-Germanic · inherited from*undurniz“interval”
3. Old English · inherited fromundern“third hour of the day; nine o'clock; morning”
4. Middle English · inherited fromundern
5. English todayundern

From Middle English undern, ondern, from Old English undern (“third hour of the day; nine o'clock; morning”), from Proto-Germanic *undurniz (“interval”), from Proto-Indo-European *h₁n̥ter, *h₁enter (“between”). Cognate with dialectal Dutch onder, dialectal German Untern, dialectal Swedish undarn.

First known use, by meaning

• 10th–15th c. Synonym of terce: the third hour of daylight (about 9 am).
• 14th–15th c. Synonym of noon: the sixth hour of daylight (12 pm).
• from 15th c. Synonym of afternoon.
• from 15th c. Synonym of evening.
• from 17th c. A light meal, particularly in the afternoon.