(Internet slang, leetspeak) Alternative spelling of leet

Abbreviation of thirteenth.

(physics, medicine) The radioactive isotope of iodine, ¹³¹₅₃I, having a half-life of eight days; used as a medical tracer

A radioactive isotope of caesium, ¹³⁷₅₅Cr, having 55 protons and 82 neutrons and which is formed mainly as a fission product by nuclear fission.

Alternative spelling of Friday the thirteenth

(Singapore, generally attributive) a one-month (or more) bonus paid to employees at the end of the financial year.

plural of 13th month

plural of Friday the 13th

Alternative form of Pluto (Minor-planet designation for the dwarf planet)

Alternative form of Pluto (Minor-planet designation for the dwarf planet)