means A favorable set of circumstances that makes a particular action or goal possible at a given moment.

from From Latin opportunitas, built on the phrase ob portum veniens — 'coming toward the harbor.' The image is a sailor's: a wind blowing fair toward port, the rare moment when sea and weather conspire to let you in. Latin opportunus literally meant 'before the harbor,' and from that nautical luck came the broader sense of any well-timed chance, arriving in English through Old French in the late medieval period.