The Collaborative International Dictionary of English v.0.48:
Upthrow \Up*throw"\, v. t. To throw up. --Drayton. [1913 Webster]The Collaborative International Dictionary of English v.0.48:
Upthrow \Up"throw`\, n. (Mining) See Throw, n., 9. [1913 Webster]WordNet (r) 3.0 (2006):
upthrow n 1: (geology) a rise of land to a higher elevation (as in the process of mountain building) [syn: upheaval, uplift, upthrow, upthrust]