[awr-thuh-hahy-druh-juh n]

noun Physics, Chemistry.

the form of molecular hydrogen in which the nuclei of the two hydrogen atoms contained in the molecule have spins in the same direction.

Compare parahydrogen.

Origin of orthohydrogen

First recorded in 1925–30; ortho- + hydrogen
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for orthohydrogen



chem the form of molecular hydrogen, constituting about 75 per cent of the total at normal temperatures, in which the nuclei of the atoms spin in the same directionCompare parahydrogen
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012