What does Boxing Day have to do with boxing?
1680s, from engineer (n.). Meaning "work done by an engineer" is from 1720. As a field of study, attested from 1792. An earlier word was engineership (1640s); engineery was attempted in 1793, but it did not stick.
early 14c., "constructor of military engines," from Old French engigneor, from Late Latin ingeniare (see engine); general sense of "inventor, designer" is recorded from early 15c.; civil sense, in reference to public works, is recorded from c.1600. Meaning "locomotive driver" is first attested 1832, American English. A "maker of engines" in ancient Greece was a mekhanopoios.