From Wiktionary, the free dictionary

level set (plural level sets)

1. (mathematical analysis) The set of values x for which a real-valued function f(x) is equal to a given constant.

• level curve
• level hypersurface
• level surface

level set (third-person singular simple present level sets, present participle level setting, simple past and past participle level set)

1. (business) To establish a baseline of mutual understanding

   Before we start the negotiation, let's level set until we all agree on a starting point.

level set (plural level sets)

1. (business) An event consisting of level setting
2. (business) A state of mutual understanding among parties

   We need to have a level set before we can go on, just so we're all on the same page.

This concept is sometimes used during major transitions in a business, to make sure all parties agree on a starting position and that their subsequent actions are coordinated.

• (mutual understanding): agreement

• Mathworld article on level sets

• levelest