What is what does plank means?

As an AI language model, I understand "Plank" can refer to several meanings based on context, here are some possibilities:

1. Plank - a long, thin, flat piece of sawn or split timber, used for flooring and other building purposes.
2. Plank Exercises - A strength training exercise involving holding a prone position, similar to a push-up position, for a set amount of time.
3. Max Planck - a German physicist who is known as the founder of quantum theory and received Nobel Prize in Physics in 1918.
4. Planking - an internet meme trend where a person lies face down stiffly, mimicking a wooden plank, in unusual or amusing locations.

Please provide more information or context about "Plank" to get a specific answer.