noun
hap
HAP/hˈæp/
Chance determining the course of an event.
By hap, the gardener discovers an unusual clover among the plants.

Etymology
Old Norse happ appears to have referred only to favorable chance. English hap also covered luck or fate more generally, as well as an unforeseen occurrence.
More examples
- By hap, we arrive at the station at the same time.
- She credits her success to hard work, not hap.
- A lucky hap brings the old friends together.
Forms
hap · haps
happen verb — To take place or come about.
hapless adjective — Unlucky and often deserving of sympathy.