The action of yawning; opening the mouth widely and taking a long, rather deep breath, often because one is tired or bored.

A particularly boring event.

“The slideshow we sat through was such a yawn. I was glad when it finished.”

To open the mouth widely and take a long, rather deep breath, often because one is tired or bored, and sometimes accompanied by pandiculation.

“I could see my students yawning, so I knew the lesson was boring them.”

To say while yawning.

To present a wide opening.

“Death yawned before us, and I hit the brakes.”