Definitions

1. interjection

a sound expressing approval, agreement, or interest

“She nodded and said ‘mm’ when I asked her if she liked the dessert.”

2. verb

to eat or drink noisily, especially with pleasure or satisfaction

“The children were mm-ing away their ice cream cones.”

3. noun

a unit of measurement, especially for audio frequency or audio volume

“The sound system was set to mm for the concert.”

4. abbreviation

millimeter

“The length of the pencil was 10 mm.”