The Collaborative International Dictionary of English v.0.48:

Petit mal \Pe*tit" mal"\ [F., lit., little sickness.] (Med.)
   The mildest form of epilepsy, with momentary faintness or
   unconsciousness, but without convulsions; -- opposed to
   grand mal.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

petit mal
    n 1: epilepsy characterized by paroxysmal attacks of brief
         clouding of consciousness (and possibly other
         abnormalities); "she has been suffering from petit mal
         since childhood" [syn: petit mal epilepsy, petit mal,
         epilepsia minor]
    2: a seizure of short duration characterized by momentary
       unconsciousness and local muscle spasms or twitching; "the
       girl was frightened by her first petit mal" [syn: petit
       mal, epilepsia minor]

Moby Thesaurus II by Grady Ward, 1.0:

74 Moby Thesaurus words for "petit mal":
   Jacksonian epilepsy, Rolandic epilepsy, abdominal epilepsy, access,
   acquired epilepsy, activated epilepsy, affect epilepsy,
   akinetic epilepsy, apoplexy, arrest, attack, autonomic epilepsy,
   blockage, cardiac epilepsy, clonic spasm, clonus, convulsion,
   cortical epilepsy, cramp, cursive epilepsy, diurnal epilepsy,
   eclampsia, epilepsia, epilepsia gravior, epilepsia major,
   epilepsia minor, epilepsia mitior, epilepsia nutans,
   epilepsia tarda, epilepsy, falling sickness, fit, focal epilepsy,
   frenzy, grand mal, haute mal, hysterical epilepsy, ictus,
   larval epilepsy, laryngeal epilepsy, laryngospasm, latent epilepsy,
   lockjaw, matutinal epilepsy, menstrual epilepsy,
   musicogenic epilepsy, myoclonous epilepsy, nocturnal epilepsy,
   occlusion, paroxysm, physiologic epilepsy, psychic epilepsy,
   psychomotor epilepsy, reflex epilepsy, rotatoria, seizure,
   sensory epilepsy, serial epilepsy, spasm, stoppage, stroke,
   tardy epilepsy, tetanus, tetany, throes, thromboembolism,
   thrombosis, tonic epilepsy, tonic spasm, torsion spasm,
   traumatic epilepsy, trismus, ucinate epilepsy, visitation