Merriam-Webster's Collegiate® Dictionary, 11th Edition
TENSE
I. noun
Etymology: Middle English tens time, tense, from Anglo-French, from Latin tempus
Date: 14th century
a distinction of form in a verb to express distinctions of time or duration of the action or state it denotes,
2. a set of inflectional forms of a verb that express distinctions of time, an inflectional form of a verb expressing a specific time distinction,
II. adjective (tenser; tensest) see: thin
Date: 1668
stretched tight ; made taut ; rigid ,
2. feeling or showing nervous tension , marked by strain or suspense , produced with the muscles involved in a relatively tense state , tensely adverb tenseness noun
III. verb (tensed; tensing)
Date: 1676
transitive verb to make tense, intransitive verb to become tense