/un'deuhr koohl"/ , v.t.
1. Chem.
a. to cool less than necessary for a given process or purpose.
b. to supercool.
2. Metall. to cool (molten metal) without forming crystals to a temperature below that at which crystallization normally takes place: Metal must be absolutely still to be undercooled.
[ 1900-05; UNDER- + COOL ]