1. (noun)Thursday, Th the fifth day of the week; the fourth working day
2. (noun)thorium, Th, atomic number 90 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
Definition of 'TH'
Webster Dictionary
1. TH in Old English, the article the, when the followingword 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
Definitions of TH 
