Source : Webster's Revised Unabridged Dictionary (1913)

T \T\ (t[=e]),
   the twentieth letter of the English alphabet, is a nonvocal
   consonant. With the letter h it forms the digraph th, which
   has two distinct sounds, as in thin, then. See Guide to
   Pronunciation, [sect][sect]262-264, and also [sect][sect]153,
   156, 169, 172, 176, 178-180. The letter derives its name and
   form from the Latin, the form of the Latin letter being
   further derived through the Greek from the Ph[oe]nician. The
   ultimate origin is probably Egyptian. It is etymologically
   most nearly related to d, s, th; as in tug, duke; two, dual,
   L. duo; resin, L. resina, Gr. "rhti`nh, tent, tense, a.,
   tenuous, thin; nostril, thrill. See {D}, {S}.

   {T bandage} (Surg.), a bandage shaped like the letter T, and
      used principally for application to the groin, or
      perineum.

   {T cart}, a kind of fashionable two seated wagon for pleasure
      driving.

   {T iron}.
   (a) A rod with a short crosspiece at the end, -- used as a
       hook.
   (b) Iron in bars, having a cross section formed like the
       letter T, -- used in structures.

   {T rail}, a kind of rail for railroad tracks, having no
      flange at the bottom so that a section resembles the
      letter T.

   {T square}, a ruler having a crosspiece or head at one end,
      for the purpose of making parallel lines; -- so called
      from its shape. It is laid on a drawing board and guided
      by the crosspiece, which is pressed against the straight
      edge of the board. Sometimes the head is arranged to be
      set at different angles.

   {To a T}, exactly, perfectly; as, to suit to a T. [Colloq.]

T square \T" square`\
   See under {T}.