Atoms of the same element that have different masses are called isotopes. Different masses result when there are different numbers of neutrons. All atoms of a particular element have the same number...
Definition of absent. 1 : not present at a usual or expected place : missing was absent from class today sharing memories of absent friends She was conspicously absent [=her absence was very noticeable] at the meeting. absently. adverb He replied absently to her question. Examples of absent in a sentence.
Define missing. missing synonyms, missing pronunciation, missing translation, English dictionary definition of missing. adj. 1. a. Not present; absent. b. Lost: a missing person; soldiers missing in action. 2. Lacking; wanting: This book has 12 missing pages. adj 1.