Definition & Meaning of "by jove"in English

What is the origin of the exclamation "by Jove" and how is it used?

By Jove is an exclamation used to express surprise, amazement, or determination. It originated in British English in the 17th century as a mild oath invoking Jove (another name for the Roman god Jupiter) instead of directly swearing by God, following a common practice of using mythological references in place of sacred ones. People used it in literature, theater, and everyday speech to emphasize strong feelings without offending religious sensibilities. Today it sounds old-fashioned, literary, and inoffensive, often adding a dramatic or emphatic flair to expressions of astonishment, resolve, or excitement.