noun: 1. Chance; fortune; 2. An occurrence.
verb tr.: 1. To occur; 2. To clothe, cover, or wrap.

For noun and verb 1: From Old Norse happ (good luck). Ultimately from the Indo-European root kobe (to suit, fit, or succeed), which also gave us happen, happy, hapless, and mishap. Earliest documented use: 1350.
For verb 2: Of uncertain origin. Earliest documented use: 1390.

HAAP - a large musical instrument with many strings, when played by the Boston Symphony Orchestra

HAPO - a curly-haired comedian who never-spoke but did play the haap, when he appeared in Boston

IHAP - where he got a pancake breakfast during these Boston appearances