The Collaborative International Dictionary of English v.0.48:

Th \Th\
   In Old English, the article the, when the following word
   began with a vowel, was often written with elision as if a
   part of the word. Thus in Chaucer, the forms thabsence,
   tharray, thegle, thend, thingot, etc., are found for the
   absence, the array, the eagle, the end, etc.
   [1913 Webster] Thack

WordNet (r) 3.0 (2006):

Th
    n 1: the fifth day of the week; the fourth working day [syn:
         Thursday, Th]
    2: a soft silvery-white tetravalent radioactive metallic
       element; isotope 232 is used as a power source in nuclear
       reactors; occurs in thorite and in monazite sands [syn:
       thorium, Th, atomic number 90]

The Free On-line Dictionary of Computing (30 December 2018):

th

    The country code for Thailand.

   (1999-01-27)