I am surprised that this word is not here yet....now it is.
Etymology is the study of the origins of words. Some words have been derived from other languages, possibly in a changed form (the source words are called etymons). Through old texts and comparisons with other languages, etymologists try to reconstruct the history of words — when they entered a language, from what source, and how their form and meaning changed.
A word often misused and mispronounced 'entymology' which is the study of insects!
Etymology in action:
"The etymologist spent hours describing the origin of the word "nice" to the students. Unfortunately no one understood what he was talking about and were all in a deep slumber after 10 minutes."
"The dean spent weeks trying to track down the entymologist to give a lecture on the derivation of the word 'aunt.' When the entymologist finally arrived discussing the workings of one of the most interesting insects on Earth, the dean was promptly fired for being a fraud."