The Collaborative International Dictionary of English v.0.48:

Tense \Tense\, n. [OF. tens, properly, time, F. temps time,
   tense. See Temporal of time, and cf. Thing.] (Gram.)
   One of the forms which a verb takes by inflection or by
   adding auxiliary words, so as to indicate the time of the
   action or event signified; the modification which verbs
   undergo for the indication of time.
   [1913 Webster]

   Note: The primary simple tenses are three: those which
         express time past, present, and future; but these admit
         of modifications, which differ in different languages.
         [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Tense \Tense\, a. [L. tensus, p. p. of tendere to stretch. See
   Tend to move, and cf. Toise.]
   Stretched tightly; strained to stiffness; rigid; not lax; as,
   a tense fiber.
   [1913 Webster]

         The temples were sunk, her forehead was tense, and a
         fatal paleness was upon her.             --Goldsmith.
   [1913 Webster] -- Tense"ly, adv. -- Tense"ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

tense
    adj 1: in or of a state of physical or nervous tension [ant:
           relaxed]
    2: pronounced with relatively tense tongue muscles (e.g., the
       vowel sound in `beat') [ant: lax]
    3: taut or rigid; stretched tight; "tense piano strings" [ant:
       lax]
    n 1: a grammatical category of verbs used to express
         distinctions of time
    v 1: become stretched or tense or taut; "the bodybuilder's neck
         muscles tensed;" "the rope strained when the weight was
         attached" [syn: strain, tense]
    2: increase the tension on; "alternately relax and tense your
       calf muscle"; "tense the rope manually before tensing the
       spring"
    3: become tense, nervous, or uneasy; "He tensed up when he saw
       his opponent enter the room" [syn: tense, tense up] [ant:
       decompress, loosen up, relax, slow down, unbend,
       unwind]
    4: cause to be tense and uneasy or nervous or anxious; "he got a
       phone call from his lawyer that tensed him up" [syn: tense,
       strain, tense up] [ant: loosen up, make relaxed,
       relax, unlax, unstrain, unwind]

Moby Thesaurus II by Grady Ward, 1.0:

276 Moby Thesaurus words for "tense":
   accented, agitated, all-overish, alveolar, antsy, anxious,
   anxioused up, aorist, apical, apico-alveolar, apico-dental,
   apprehensive, articulated, assimilated, back, barytone, bilabial,
   bothered, brace, broad, cacuminal, central, cerebral, checked,
   chill, chilly, chronology, close, cold, concerned, consonant,
   consonantal, continuant, continue, continuity, cool, dental,
   disaccordant, disquieted, disquieting, dissimilated, distressed,
   distressing, disturbed, disturbing, dorsal, drag out, dragged out,
   draw, draw out, drawn, drawn out, duration, durative, duree, edgy,
   elongate, elongated, extend, extended, fearful, fidgety, firm,
   flat, fluttery, foreboding, fraught, front, frosty, fussy, future,
   future perfect, glide, glossal, glottal, guttural, hard, haul,
   heave, heavy, high, high-strung, historical present, icy,
   imperfect, in a pucker, in a stew, in suspense, incompatible,
   inhospitable, inimical, intense, intonated, jittery, jumpy,
   keyed up, keyed-up, labial, labiodental, labiovelar, lastingness,
   lateral, lax, lengthen, lengthen out, lengthened, let out, light,
   lingual, liquid, low, mid, misgiving, monophthongal, muted, narrow,
   nasal, nasalized, nerve-racking, nervous, nervy, occlusive,
   on edge, on tenterhooks, on tiptoe, open, overanxious,
   overapprehensive, overexert, overextend, overstrain, overtax,
   overwrought, oxytone, palatal, palatalized, past, past perfect,
   perfect, period, perturbed, pharyngeal, pharyngealized, phonemic,
   phonetic, phonic, pitch, pitched, pluperfect, point tense,
   pokerlike, posttonic, present, present perfect, press, preterit,
   produce, progressive tense, prolong, prolongate, prolongated,
   prolonged, protract, protracted, psychological time, pull, pulled,
   queasy, quivering, rack, ramrodlike, reinforce, renitent, restive,
   restless, retroflex, rigid, rigidify, rodlike, rounded, rusty,
   screw up, semivowel, shore up, soft, solicitous, sonant, space,
   space-time, spin out, spun out, starched, starchy, stiff,
   stiff as buckram, stiffen, stopped, straggling, strain,
   strain every nerve, strained, strengthen, stress, stressed,
   stressful, stretch, stretch out, stretched, stretched out,
   stretched tight, string out, strong, strung out, surd, suspenseful,
   sweat blood, syllabic, taut, tauten, tax, tension, term,
   the future, the past, the present, thick, throaty, tide, tight,
   tighten, time, timebinding, tonal, tonic, trice up, troubled, tug,
   twangy, unaccented, unamiable, unamicable, uncordial,
   under a strain, uneasy, unfriendly, ungenial, unharmonious,
   unquiet, unrelaxed, unrestful, unrounded, unsettled, unsociable,
   unstressed, upset, uptight, velar, virgate, vocalic, vocoid,
   voiced, voiceless, vowel, vowellike, weak, while, wide,
   with bated breath, with muscles tense, worked up, worried,
   worrisome, worrying, wound up, wrought up, zealous



The Jargon File (version 4.4.7, 29 Dec 2003):

tense
 adj.

    Of programs, very clever and efficient. A tense piece of code often got
    that way because it was highly tuned, but sometimes it was just based on a
    great idea. A comment in a clever routine by Mike Kazar, once a
    grad-student hacker at CMU: ?This routine is so tense it will bring tears
    to your eyes.? A tense programmer is one who produces tense code.


The Free On-line Dictionary of Computing (30 December 2018):

tense

   Of programs, very clever and efficient.  A tense piece of code
   often got that way because it was highly bummed, but
   sometimes it was just based on a great idea.  A comment in a
   clever routine by Mike Kazar, once a grad-student hacker at
   CMU: "This routine is so tense it will bring tears to your
   eyes."  A tense programmer is one who produces tense code.

   [Jargon File]


Bouvier's Law Dictionary, Revised 6th Ed (1856):

TENSE. A term used in, grammar to denote the distinction of time.
     2. The acts of a court of justice ought to be in the present tense; as,
"praeceptum est," not "preaceptum fuit;" but the acts of, the party may be
in the preterperfect tense, as "venit, et protulit hic in curia quandum
querelam suam;" and the continuances are in the preterperfect tense; as,
"venerunt," not "veniunt." 1 Mod. 81.
     3. The contract of marriage should be made in language in the present
tense. 6 Binn. Rep. 405. Vide 1 Saund. 393, n. 1.