1. To assume the existence of; to postulate: Dr. James, the scientist, posited that black holes in the universe predated the existence of the stars.
2. To put forward, as for consideration or study; to suggest an idea or theory; especially, in order to begin a discussion: The astronomers, Tom and Gerry, posited that the stars and the universe are composed of mysterious dark holes.
3. To place something firmly in place: Blacky, the mule, posited its foot firmly on the bridge before starting to walk across it.

The workers, Doug and Gary, were positing special square stone pieces to construct the driveway instead of making a solid concrete one.