a compound with molecule-size pores, as some sodium aluminum silicates, that chemically locks molecules in them: used in purification and separation processes.
Origin of molecular sieve
First recorded in 1925–30
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British Dictionary definitions for molecular sieve
chem a material that can absorb large amounts of certain compounds while not absorbing others and is thus suitable for use in separating mixtures
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