lofthead

English

Etymology

loft +‎ head

Noun

lofthead (plural loftheads)

1. (obsolete, rare) An overhead cavity in a cave or mineshaft caused by a fall of roof.
   • 1880, Transactions of the Manchester Geological Society:

     If a certain vacant space is left above the timbering of a road, it often affords a lodgment for gas, and it is by no means easy to ventilate such a space, or, as it is often called, a "lofthead," in all cases.

References

• United States Bureau of Mines, Dictionary of Mining, Mineral, and Related Terms (1996).