Hm Definition

abbreviation
Hectometer.
American Heritage
Hectometer(s)
Webster's New World
Hazardous material.
Webster's New World
Her (or His) Majesty.
Webster's New World

The ccTLD for Heard Island and McDonald Islands as assigned by the IANA.

Wiktionary
interjection

Alternative form of hmm.

Wiktionary

Words Near Hm in the Dictionary