To boil gently, or with a gentle hissing; to begin to boil.
- To be cooked gently or remain just at or below the boiling point.
- To be filled with pent-up emotion; seethe.
- To be in a state of gentle ferment: thoughts simmering in the back of her mind.
- To cook (food) gently in a liquid just at or below the boiling point.
- To keep (a liquid) near or just below the boiling point. See Synonyms at boil1.
- The state or process of simmering.
- simmer down To become calm after excitement or anger.