Definition -
(1) A history of the origin and evolution of a word.
(2) The area of study that concerns itself with the history of words.

Etymology -
The word derives from the Greek etymologia, which itself derives from the Greek etymon, true sense.
Note: The etymology of etymology perhaps implies that a word's primordial meaning is its true meaning. This is called the etymological fallacy.

Oxford English Dictionary -
The term's first citation in this sense is from 1646:
"Others have better observed the laws of Etymology, and deduced it from a word of the same language."
(Sir T. Browne Pseud. Ep. ii. vi. 93)

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