[1] : The Collaborative International Dictionary of English v.0.48

problem \prob"lem\, n. f. probl`eme, l. problema, fr. gr. ?
   anything thrown forward, a question proposed for solution,
   fr. ? to throw or lay before; ? before, forward + ? to throw.
   cf. parable. 
   1913 webster
   1. a question proposed for solution; a matter stated for
      examination or proof; hence, a matter difficult of
      solution or settlement; a doubtful case; a question
      involving doubt. --bacon.
      1913 webster

   2. math. anything which is required to be done; as, in
      geometry, to bisect a line, to draw a perpendicular; or,
      in algebra, to find an unknown quantity.
      1913 webster

   note: problem differs from theorem in this, that a problem is
         something to be done, as to bisect a triangle, to
         describe a circle, etc.; a theorem is something to be
         proved, as that all the angles of a triangle are equal
         to two right angles.
         1913 webster

   plane problem geom., a problem that can be solved by the
      use of the rule and compass.

   solid problem geom., a problem requiring in its geometric
      solution the use of a conic section or higher curve.
      1913 webster problematic
see also:
parable plane problem solid problem 

[2] : WordNet (r) 2.0

problem
     n 1: a state of difficulty that needs to be resolved; "she and
          her husband are having problems"; "it is always a job to
          contact him"; "urban problems such as traffic congestion
          and smog" syn: job
     2: a source of difficulty; "one trouble after another delayed
        the job"; "what's the problem?" syn: trouble
     3: a question raised for consideration or solution; "our
        homework consisted of ten problems to solve"
see also:
job trouble 

[3] : Moby Thesaurus II by Grady Ward, 1.0

196 moby thesaurus words for "problem":
   chinese puzzle, ado, aggravation, annoyance, anxiety, bad news,
   baffle, bafflement, baffling problem, basis, bedevilment,
   besetment, bewilderment, blemish, bone of contention, bore, bother,
   botheration, bothersomeness, brain twister, bug, bugaboo, bugbear,
   burden, can of worms, case, catch, catechism, chapter,
   complication, concern, confoundment, confusion, conundrum, count,
   crack, crashing bore, cross-interrogatory, cross-question,
   crossword puzzle, crux, debating point, defect, defection,
   deficiency, delinquent, demand, devilment, difficult, difficulty,
   dilemma, disadvantage, discomposure, disconcert, disconcertedness,
   disconcertion, disconcertment, disturbance, disturbed, dogging,
   downer, drag, drawback, embarrassment, enigma, enigmatic question,
   essence, evil, exasperation, facer, failing, failure, fault, faute,
   feeler, fix, flaw, floorer, focus of attention, focus of interest,
   foible, frailty, gist, great ado, harassment, harrying, head,
   headache, heading, hole, hounding, illustration, imbroglio,
   imperfection, inadequacy, inconvenience, incorrigible, infirmity,
   inquiry, interrogation, interrogative, interrogatory, intractable,
   issue, jam, jigsaw puzzle, kink, knot, knotty point, leader,
   leading question, little problem, living issue, main point,
   maladjusted, matter, matter in hand, meat, mess, mind-boggler,
   molestation, moot point, motif, motive, muddle, mystery, nonplus,
   nuisance, nut, nut to crack, obstreperous, peck of troubles,
   perplexed question, perplexity, persecution, perturbation, pest,
   pickle, plight, point, point at issue, point in question, poser,
   pother, predicament, pretty pickle, puzzle, puzzlement, puzzler,
   quandary, query, question, question at issue, question mark,
   quodlibet, refractory, riddle, rift, rubric, scrape,
   sea of troubles, shortcoming, sixty-four dollar question, snag,
   something missing, stew, sticker, stumper, subject, subject matter,
   subject of thought, substance, taint, text, theme, topic,
   tough proposition, trial, trial balloon, trouble, unassuredness,
   uncontrollable, ungovernable, unmanageable, unruly, upset,
   vexation, vexatiousness, vexed question, vulnerable place,
   weak link, weak point, weakness, why, worriment, worry

Problem >> P Words
Problem, definition of term: Problem
problem_pag1.html

Problem Solving >> P Words
Problem Solving, definition of term: Problem Solving
problem+solving_pag1.html

Health Problem >> H Words
Health Problem, definition of term: Health Problem
health+problem_pag1.html