The Collaborative International Dictionary of English v.0.48:

Latent \La"tent\ (l[=a]"tent), a. [L. latens, -entis, p. pr. of
   latere to lie hid or concealed; cf. Gr. lanqa`nein, E.
   lethargy: cf. F. latent.]
   1. Not visible or apparent; hidden; concealed; secret;
      dormant; as, latent springs of action.
      [1913 Webster]

            The evils latent in the most promising contrivances
            are provided for as they arise.       --Burke.
      [1913 Webster]

   2. (Med.) Existing but not presenting symptoms; dormant or
      developing; -- of disease, especially infectious diseases;
      as, the latent phase of an infection.
      [PJC]

   Latent buds (Bot.), buds which remain undeveloped or
      dormant for a long time, but may eventually grow.

   Latent heat (Physics), that quantity of heat which
      disappears or becomes concealed in a body while producing
      some change in it other than rise of temperature, as
      fusion, evaporation, or expansion, the quantity being
      constant for each particular body and for each species of
      change; the amount of heat required to produce a change of
      phase.

   Latent period.
      (a) (Med.) The regular time in which a disease is supposed
          to be existing without manifesting itself.
      (b) (Physiol.) One of the phases in a simple muscular
          contraction, in which invisible preparatory changes
          are taking place in the nerve and muscle.
      (c) (Biol.) One of those periods or resting stages in the
          development of the ovum, in which development is
          arrested prior to renewed activity.
          [1913 Webster]

WordNet (r) 3.0 (2006):

latent
    adj 1: potentially existing but not presently evident or
           realized; "a latent fingerprint"; "latent talent"
    2: (pathology) not presently active; "latent infection"; "latent
       diabetes"

Moby Thesaurus II by Grady Ward, 1.0:

145 Moby Thesaurus words for "latent":
   abeyant, abstruse, apathetic, arcane, beclouded,
   behind the curtain, behind the scenes, between the lines, blind,
   buried, cabalistic, camouflaged, cataleptic, catatonic, censored,
   classified, close, closed, clouded, concealed, covered, covert,
   cryptic, dark, dead, delitescent, disguised, dopey, dormant, dull,
   eclipsed, enigmatic, esoteric, flat, foul, groggy, heavy, hermetic,
   hibernating, hid, hidden, hush-hush, idle, immature, imperceptible,
   in a cloud, in a fog, in abeyance, in eclipse, in purdah,
   in suspense, in the wings, inactive, incommunicado, indiscernible,
   inert, insensible, invisible, languid, languorous, leaden,
   lifeless, logy, lurking, muffled, mysterious, mystic, obfuscated,
   obscure, obscured, occult, out of sight, passive, phlegmatic,
   possible, potential, quiescent, recondite, restricted, secluded,
   secluse, secret, sedentary, sequestered, sightless, slack,
   sleeping, sluggish, slumbering, smoldering, smothered, stagnant,
   standing, static, stifled, submerged, suppressed, suspended, tame,
   top secret, torpid, ulterior, unapparent, unaroused, unbeheld,
   unbeholdable, unbreatheable, under an eclipse, under cover,
   under house arrest, under security, under the surface, under wraps,
   underground, underlying, undiscernible, undisclosable, undisclosed,
   undivulgable, undivulged, unknown, unmanifested, unmatured,
   unnoticed, unobserved, unperceivable, unperceived, unrealized,
   unrevealable, unrevealed, unripe, unseeable, unseen, unspoken,
   untellable, untold, unutterable, unuttered, unviewed,
   unwhisperable, unwitnessed, veiled, viewless, virtual,
   wrapped in clouds



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

LATENT, construction. That which is concealed; or which does not appear; for
example, if a testator bequeaths to his cousin Peter his white horse; and at
the time of making his will and at his death he had two cousins named Peter,
and he owned two white horses, the ambiguity in this case would be latent,
both as respects the legatee, and the thing bequeathed. Vide Bac. Max. Reg.
23, and article Ambiguity. A latent ambiguity can only be made to appear by
parol evidence, and may be explained by the same kind of proof. 5 Co. 69.