/ Dictionary / Index U ultramicrometer: Meaning and Definition of Find definitions for: ul•tra•mi•crom•e•ter Pronunciation: (ul"tru-mī-krom'i-tur), [key] — n. a micrometer calibrated to a very fine scale and capable of measuring extremely small magnitudes. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. ultramicrofiche ultramicroscope Related Content Daily Word Quiz: slough Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language