/ · 1894 Brewer’s · N · nth, or nth plus One
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
in University slang, means to the utmost degree. Thus, Cut to the nth means wholly unnoticed by a friend. The expression is taken from the index of a mathematical formula, where n stands for any number, and n + 1, one more than any number.
· ·
Entry taken from Dictionary of Phrase and Fable, edited by the Rev. E. Cobham Brewer, LL.D. and revised in 1895.
· 
· 