yawn

American Heritage® Dictionary of the English Language, Fourth Edition

1. v. To open the mouth wide with a deep inhalation, usually involuntarily from drowsiness, fatigue, or boredom.
2. v. To open wide; gape: The chasm yawned at our feet.
3. v. To utter wearily, while or as if while yawning: yawned his disapproval of the silly venture.
4. n. The act of yawning.
5. n. A fatigued or bored response.
6. n. Informal One that provokes yawns; a bore: The movie was nothing more than one big yawn.

Century Dictionary and Cyclopedia

1. To gape; open; stand wide.
2. Specifically.
3. To open the mouth wide. Voluntarily.
4. Involuntarily, as through drowsiness or dullness; gape; oscitate. Compare yawning.
5. To gape, as in hunger or thirst for something; hence, to be eager; long.
6. To be open-mouthed with surprise, bewilderment, etc.; be agape.
7. To open; form by opening.
8. To express or utter with a yawn.
9. n. The act of gaping or opening wide.
10. n. An involuntary opening of the mouth from drowsiness; oscitation. See yawning.
11. n. An opening; a chasm.

Wiktionary

1. v. To open the mouth widely and take a long, rather deep breath, often because one is tired and sometimes accompanied by pandiculation.
2. v. To present an opening that appears able to swallow one up, literally or metaphorically:
3. n. The action of yawning; opening the mouth widely and taking a long, rather deep breath, often because one is tired.
4. n. A particularly boring event.

GNU Webster's 1913

1. v. To open the mouth involuntarily through drowsiness, dullness, or fatigue; to gape; to oscitate.
2. v. To open wide; to gape, as if to allow the entrance or exit of anything.
3. v. To open the mouth, or to gape, through surprise or bewilderment.
4. v. To be eager; to desire to swallow anything; to express desire by yawning.
5. n. An involuntary act, excited by drowsiness, etc., consisting of a deep and long inspiration following several successive attempts at inspiration, the mouth, fauces, etc., being wide open.
6. n. The act of opening wide, or of gaping.
7. n. rare A chasm, mouth, or passageway.

WordNet 3.0

1. v. utter a yawn, as from lack of oxygen or when one is tired
2. v. be wide open
3. n. an involuntary intake of breath through a wide open mouth; usually triggered by fatigue or boredom