Etymology is the part of linguistics (the scientific study of language) that explores the history of words. Etymology can trace the evolution and changes in both pronunciation and meanings of words. Etymology is not really an occupation: it is an interesting hobby that leads into history as well as a better understanding of the language. Then there are times when we run into some interesting, and perhaps surprising connections. For example “exit” and “coitus” share a common origin.
Let’s start with exit. The Latin base for “exit” is “exīre” meaning “to go out.” The Latin is from the prefix “ex” meaning “out” and the verb “īre” meaning “to go.” This is the same Latin base for the English “issue.”
“Exit” began its life in English in the theater as a stage direction. It literally means “he or she goes out.” In the seventeenth century, “exit” began to be used to mean “way out” and then in the nineteenth century it started to be used to indicate “door by which one leaves.”
English is, of course, a Germanic language which has acquired Latin vocabulary over the past 1,000 years through the French-speaking Norman invasion of 1066 and through technical and academic vocabulary from the Roman Catholic Church and science.
If we go back farther in time, we will find that both the Germanic languages and Latin have their origin in Proto-Indo-European. The designation “proto” indicates a language which has been reconstructed by linguistics but is not really used today. The Latin verb “īre” stems from the Proto-Indo-European *ei (linguists use the * to indicate that the word has been reconstructed) which was used to form “coitus,” “obituary,” and “transient.”
“Coitus” is from the past participle of the Latin verb “coīre” which is formed from the prefix “co” meaning “together” and the verb “īre” meaning “to go.”
“Obituary” also comes from a compound Latin verb “obīre” meaning “to go down” which is formed from the prefix “ob” meaning “down” and the verb “īre” meaning “to go.”
“Transient” is based on the present participle of the Latin verb “trānsīre” meaning “to go across, over” which is formed from the prefix “trāns” meaning “across, over” and the verb “īre” meaning “to go.” The Latin “trānsīre” is also the basic of the English words “trance,” “transit,” and “transition.”