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.
Adj. 1. relevant-having a bearing on or connection with the subject at issue; the scientist corresponds with colleagues in order to learn about matters relevant to her own research. irrelevant-having no bearing on or connection with the subject at issue; an irrelevant comment; irrelevant allegations.