- Thursday, Th - the fifth day of the week; the fourth working day
--1 is a kind of weekday
- 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
--2 is a kind of metallic element, metal
--2 is a substance of monazite; thorite
--2 has particulars: thorium-228, radiothorium