Beware, older languages below! The languages below were invented during Tolkien's earlier period and should be used with caution. Remember to never, ever mix words from different languages!

Qenya 

enatwa

adjective. the second (of two)

A word meaning “the second (of two)” appearing in Demonstrative, Relative, and Correlative Stems (DRC) from 1948 as a combination of demonstrative en with atwa “either” (PE23/107 and note #83). Presumably when given an either/or choice, enatwa would be used when you choose the second option.