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.
1. not in a certain place at a given time; away; missing; not present: absent from class. 2. lacking; nonexistent: Revenge was absent from his mind. 3. not attentive; preoccupied; absent-minded: an absent expression.