[ uhl-truh-fil-ter ]
/ ˌʌl trəˈfɪl tər /


Physical Chemistry. a filter for purifying sols, having a membrane with pores sufficiently small to prevent the passage of the suspended particles.
Mathematics. a filter in a topological space, having the property that no other filter exists in the space having among its subsets all the subsets in the given filter.

verb (used with object)

Physical Chemistry. to purify by means of an ultrafilter.

Origin of ultrafilter

OTHER WORDS FROM ultrafilter

ul·tra·fil·tra·tion [uhl-truh-fil-trey-shuh n] /ˌʌl trə fɪlˈtreɪ ʃən/, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

British Dictionary definitions for ultra filtration (1 of 2)

ultra filtration


engineering filtration that removes particles less than 10 microns (10 –6 m) in diameter

British Dictionary definitions for ultra filtration (2 of 2)

/ (ˌʌltrəˈfɪltə) /


a filter with small pores used to separate very small particles from a suspension or colloidal solution

Derived forms of ultrafilter

ultrafiltration (ˌʌltrəfɪlˈtreɪʃən), noun
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