• Webster's Revised Unabridged Dictionary
    • n Undern The time between; the time between sunrise and noon; specifically, the third hour of the day, or nine o'clock in the morning, according to ancient reckoning; hence, mealtime, because formerly the principal meal was eaten at that hour; also, later, the afternoon; the time between dinner and supper. "Betwixt undern and noon was the field all won.""In a bed of worts still he lay
      Till it was past undern of the day."
    • ***
Century Dictionary and Cyclopedia
    • n undern Nine o'clock in the morning; the period from nine o'clock to noon; the canonical hour of terce.
    • n undern Noon or afternoon; also, a noon meal.
    • ***
Chambers's Twentieth Century Dictionary
    • n Undern un′dern nine o'clock in the morning, the third hour, the period from that till noon.
    • ***


Webster's Revised Unabridged Dictionary
AS. undern,; akin to OS. undorn, OHG. untarn, untorn, Icel. undorn, mid afternoon, mid forenoon, Goth. undaúrnimats, the midday meal. Cf. Undermeal Undertime


In literature:

And on the morn at underne Sir Arthur was ready in the field with three great hosts.
"Le Morte D'Arthur, Volume II (of II)" by Thomas Malory
Then he departed from them and took his two cousins with him, and so they came unto Camelot by the hour of underne on Whitsunday.
"Chronicle and Romance (The Harvard Classics Series)" by Jean Froissart, Thomas Malory, Raphael Holinshed

In science:

Since covariance operators are undern concern within functional PCA, we should first of all define them and give some of their main features.
Local functional principal component analysis