LL.M. is an abbreviation of Latin Legum Magister, which means master of laws, In Latin, the plural from of a word is abbreviated by repeating the letter. Hence, “LL.” is short for “law”. Legum is the possessive plural from of the Latin word lex, which means “specific laws”, as opposed to the more general concept embodied in the word jus, from which the word juris and the modern English word “justice” are derived.