Meaning of immersion objective

immer'sion objec"tive

Pronunciation: [key]
— Optics. Optics.
  1. a microscope objective of high resolving power in which the space between the front lens and the cover glass is filled with an oil whose index of refraction is close to that of the objective and the cover glass. Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.