- Mining. a crossing of two passages, as airways, dug at the same level so that one descends to pass beneath the other without any opening into it.Compare overcast(def 9).
- Meteorology. an overcast layer of clouds viewed from above.
Origin of undercast
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for undercast
By noon the sky was heavily overcast, and an hour later undercast as well.The Mountains of Oregon
William Gladstone Steel
Undercast, un′dėr-kast, n. an air-passage crossing a road in a mine by means of an air-tight box or channel beneath it.