simmer

American Heritage® Dictionary of the English Language, Fourth Edition

1. v. To be cooked gently or remain just at or below the boiling point.
2. v. To be filled with pent-up emotion; seethe.
3. v. To be in a state of gentle ferment: thoughts simmering in the back of her mind.
4. v. To cook (food) gently in a liquid just at or below the boiling point.
5. v. To keep (a liquid) near or just below the boiling point. See Synonyms at boil¹.
6. n. The state or process of simmering.
7. simmer down To become calm after excitement or anger.

Century Dictionary and Cyclopedia

1. To make a gentle murmuring or hissing sound, under the action of heat, as liquids when beginning to boil; hence, to become heated gradually: said especially of liquids which are to be kept, while heating, just below the boiling-point.
2. Figuratively, to be on the point of boiling or breaking forth, as suppressed anger.
3. To cause to simmer; heat gradually: said especially of liquids kept just below the boiling-point.
4. n. A gentle, gradual, uniform heating: said especially of liquids.
5. n. A Scotch form of summer.

Wiktionary

1. n. The state or process of simmering.
2. v. intransitive To cook or undergo heating slowly at or below the boiling point.
3. v. transitive To cause to cook or to cause to undergo heating slowly at or below the boiling point.

GNU Webster's 1913

1. v. To boil gently, or with a gentle hissing; to begin to boil.
2. v. To cause to boil gently; to cook in liquid heated almost or just to the boiling point.

WordNet 3.0

1. v. boil slowly at low temperature
2. n. temperature just below the boiling point