The Collaborative International Dictionary of English v.0.48:

Strain \Strain\, v. t. [imp. & p. p. Strained; p. pr. & vb. n.
   Straining.] [OF. estraindre, estreindre, F. ['e]treindre,
   L. stringere to draw or bind tight; probably akin to Gr. ? a
   halter, ? that which is squeezwd out, a drop, or perhaps to
   E. strike. Cf. Strangle, Strike, Constrain, District,
   Strait, a. Stress, Strict, Stringent.]
   1. To draw with force; to extend with great effort; to
      stretch; as, to strain a rope; to strain the shrouds of a
      ship; to strain the cords of a musical instrument. "To
      strain his fetters with a stricter care." --Dryden.
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   2. (Mech.) To act upon, in any way, so as to cause change of
      form or volume, as forces on a beam to bend it.
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   3. To exert to the utmost; to ply vigorously.
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            He sweats,
            Strains his young nerves.             --Shak.
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            They strain their warbling throats
            To welcome in the spring.             --Dryden.
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   4. To stretch beyond its proper limit; to do violence to, in
      the matter of intent or meaning; as, to strain the law in
      order to convict an accused person.
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            There can be no other meaning in this expression,
            however some may pretend to strain it. --Swift.
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   5. To injure by drawing, stretching, or the exertion of
      force; as, the gale strained the timbers of the ship.
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   6. To injure in the muscles or joints by causing to make too
      strong an effort; to harm by overexertion; to sprain; as,
      to strain a horse by overloading; to strain the wrist; to
      strain a muscle.
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            Prudes decayed about may track,
            Strain their necks with looking back. --Swift.
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   7. To squeeze; to press closely.
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            Evander with a close embrace
            Strained his departing friend.        --Dryden.
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   8. To make uneasy or unnatural; to produce with apparent
      effort; to force; to constrain.
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            He talks and plays with Fatima, but his mirth
            Is forced and strained.               --Denham.
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            The quality of mercy is not strained. --Shak.
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   9. To urge with importunity; to press; as, to strain a
      petition or invitation.
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            Note, if your lady strain his entertainment. --Shak.
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   10. To press, or cause to pass, through a strainer, as
       through a screen, a cloth, or some porous substance; to
       purify, or separate from extraneous or solid matter, by
       filtration; to filter; as, to strain milk through cloth.
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   To strain a point, to make a special effort; especially, to
      do a degree of violence to some principle or to one's own
      feelings.

   To strain courtesy, to go beyond what courtesy requires; to
      insist somewhat too much upon the precedence of others; --
      often used ironically. --Shak.
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