Very often, in vocabulary, and the study of definitions, I have found among my students that the history of a word is seldom used as a means to understanding the word and how it's used, or changed in use.
Word history, or etymology, as the study is called, can be very valuable to a student in several ways.
First, it helps the student understand that English, as we know it, is international and multicultural. The root of a lot of words in English are derived from Greek, Latin, French, and German, and that language is not only living, but evolving. Words with prefixes and suffixes that change context can also be isolated and discussed.
Secondly, the history of a word, studied in context of its original language and spelling can make the meaning of a word come alive for a student and give them one of those much-prized "light bulb" moments that teachers live for; the student has a point of reference to make a connection, and will be more likely to remember the word the next time they encounter it.
Finally, the study of how a word might have changed in meaning or spelling can prove interesting; a research assignment on a word's etymology could be a small study project that will enhance learning new words in a way that will engage the student and make them take ownership of increasing their own vocabulary.