by Jove

From Latin pro Iovem. Ellipsis of a full oath of the form "I swear by Jove that…" Originally a literal oath; later a minced oath.

by Jove

1. (obsolete, Classics) Invocation of the Roman god Jupiter.
   • 1575, “Apius and Virginia”, in Isaac Reed, Octavius Gilchrist, editor, A Select Collection of Old Plays, London: Septimus Prowett, published 1826, page 353:

     By Jove, master marchant, by sea or by land / Would get but smale argent if I did not stand / His very good master, I may say to you, / When he hazards in hope what hap will insue.

   • a. 1639, Webster, John, Appius and Virginia, London: printed for Humphrey Moseley, published 1659, act 3, scene 1, page 38:

     By Joves help I'l^[sic] be there.

2. (dated, chiefly British) minced oath for by God, Jove referring to Jupiter.
   • 1623, William Shakespeare, Love's Labour's Lost, Act V, scene II:

     By Jove, I always took three threes for nine.

   • 1623, William Shakespeare, The Tragedy of Antony and Cleopatra, Act III, scene XIII:

     Favours, by Jove that thunders! What art thou, fellow?

   • 1916, P. G. Wodehouse, “Jeeves Takes Charge”, in A Wodehouse Miscellany:

     Well, I wasn't going to have any of that sort of thing, by Jove!

• See Thesaurus:wow

• by Jupiter