oversite

Short definition from Wiktionary

Adjective

1. 1
   Laid over the ground, or built above an existing site.

Noun

1. 1
   A layer of concrete underneath the ground floor of a building, as a seal
2. 2
   An oversite slab, a slab on grade, a flat, solid layer of concrete laid over prepared ground, usually serving as a base for flooring or for pouring the reinforced concrete floor slab (base plate).