1. [n]  something (a person or object or scene) selected by an artist or photographer for graphic representation; "a moving picture of a train is more dramatic than a still picture of the same subject"
2. [n]  some situation or event that is thought about; "he kept drifting off the topic"; "he had been thinking about the subject for several years"; "it is a matter for the police"
3. [n]  a branch of knowledge; "in what discipline is his doctorate?"; "teachers should be well trained in their subject"; "anthropology is the study of human beings"
4. [n]  one of the two main constituents of a sentence; the grammatical constituent about which something is predicated
5. [n]  (logic) the first term of a proposition
6. [n]  the subject matter of a conversation or discussion; "he didn't want to discuss that subject"; "it was a very sensitive topic"; "his letters were always on the theme of love"
7. [n]  a person who owes allegiance to that nation; "a monarch has a duty to his subjects"
8. [n]  a person who is subjected to experimental or other observational procedures; someone who is an object of investigation; "the subjects for this investigation were selected randomly"; "the cases that we studied were drawn from two different communities"
9. [adj]  being under the power or sovereignty of another or others; "subject peoples"; "a dependent prince"
10. [v]  make liable; "This action may subject you to certain penalties"
11. [v]  make vulnerable or liable to; "People in Chernobyl were subjected to radiation"
12. [v]  make accountable for; "He did not want to subject himself to the judgments of his superiors"
13. [v]  cause to experience or suffer; "He subjected me to his awful poetry"; "The sergeant subjected the new recruits to many drills"
14. [v]  make subservient; force to submit

1. \Sub*ject"\, a. [OE. suget, OF. souzget, sougit (in
   which the first part is L. subtus below, fr. sub under),
   subgiet, subject, F. sujet, from L. subjectus lying under,
   subjected, p. p. of subjicere, subicere, to throw, lay,
   place, or bring under; sub under + jacere to throw. See {Jet}
   a shooting forth.]
   1. Placed or situated under; lying below, or in a lower
      situation. [Obs.] --Spenser.
   2. Placed under the power of another; specifically
      (International Law), owing allegiance to a particular
      sovereign or state; as, Jamaica is subject to Great
      Britain.
            Esau was never subject to Jacob.      --Locke.
   3. Exposed; liable; prone; disposed; as, a country subject to
      extreme heat; men subject to temptation.
            All human things are subject to decay. --Dryden.
   4. Obedient; submissive.
            Put them in mind to be subject to principalities.
                                                  --Titus iii.
                                                  1.
   Syn: Liable; subordinate; inferior; obnoxious; exposed. See
        {Liable}.
   

2. \Sub*ject"\, n. [From L. subjectus, through an old form
   of F. sujet. See {Subject}, a.]
   1. That which is placed under the authority, dominion,
      control, or influence of something else.
   2. Specifically: One who is under the authority of a ruler
      and is governed by his laws; one who owes allegiance to a
      sovereign or a sovereign state; as, a subject of Queen
      Victoria; a British subject; a subject of the United
      States.
            Was never subject longed to be a king, As I do long
            and wish to be a subject.             --Shak.
            The subject must obey his prince, because God
            commands it, human laws require it.   --Swift.
   Note: In international law, the term subject is convertible
         with citizen.
   3. That which is subjected, or submitted to, any physical
      operation or process; specifically (Anat.), a dead body
      used for the purpose of dissection.
   4. That which is brought under thought or examination; that
      which is taken up for discussion, or concerning which
      anything is said or done. ``This subject for heroic
      song.'' --Milton.
            Make choice of a subject, beautiful and noble, which
            . . . shall afford an ample field of matter wherein
            to expatiate.                         --Dryden.
            The unhappy subject of these quarrels. --Shak.
   5. The person who is treated of; the hero of a piece; the
      chief character.
            Writers of particular lives . . . are apt to be
            prejudiced in favor of their subject. --C.
                                                  Middleton.
   6. (Logic & Gram.) That of which anything is affirmed or
      predicated; the theme of a proposition or discourse; that
      which is spoken of; as, the nominative case is the subject
      of the verb.
            The subject of a proposition is that concerning
            which anything is affirmed or denied. --I. Watts.
   7. That in which any quality, attribute, or relation, whether
      spiritual or material, inheres, or to which any of these
      appertain; substance; substratum.
            That which manifests its qualities -- in other
            words, that in which the appearing causes inhere,
            that to which they belong -- is called their subject
            or substance, or substratum.          --Sir W.
                                                  Hamilton.
   8. Hence, that substance or being which is conscious of its
      own operations; the mind; the thinking agent or principal;
      the ego. Cf. {Object}, n., 2.
            The philosophers of mind have, in a manner, usurped
            and appropriated this expression to themselves.
            Accordingly, in their hands, the phrases conscious
            or thinking subject, and subject, mean precisely the
            same thing.                           --Sir W.
                                                  Hamilton.
   9. (Mus.) The principal theme, or leading thought or phrase,
      on which a composition or a movement is based.
            The earliest known form of subject is the
            ecclesiastical cantus firmus, or plain song.
                                                  --Rockstro.
   10. (Fine Arts) The incident, scene, figure, group, etc.,
       which it is the aim of the artist to represent.
   

3. \Sub*ject"\, v. t. [imp. & p. p. {Subjected}; p. pr. &
   vb. n. {Subjecting}.]
   1. To bring under control, power, or dominion; to make
      subject; to subordinate; to subdue.
            Firmness of mind that subjects every gratification
            of sense to the rule of right reason. --C.
                                                  Middleton.
            In one short view subjected to our eye, Gods,
            emperors, heroes, sages, beauties, lie. --Pope.
            He is the most subjected, the most ?nslaved, who is
            so in his understanding.              --Locke.
   2. To expose; to make obnoxious or liable; as, credulity
      subjects a person to impositions.
   3. To submit; to make accountable.
            God is not bound to subject his ways of operation to
            the scrutiny of our thoughts.         --Locke.
   4. To make subservient.
            Subjected to his service angel wings. --Milton.
   5. To cause to undergo; as, to subject a substance to a white
      heat; to subject a person to a rigid test.
   

In subject-oriented programming, a subject is a collection of classes or class fragments whose class hierarchy models its domain in its own, subjective way. A subject may be a complete application in itself, or it may be an incomplete fragment that must be composed with other subjects to produce a complete application. Subject composition combines class hierarchies to produce new subjects that incorporate functionality from existing subjects.