Noun

1. The members used to build a (structural) crib, usually of timbers or logs, but also of concrete, steel or even plastic; cribwork.
2. As a whole, the heavy structure built to support an existing structure from underneath, as with a mineshaft or when raising a building off its foundation, as for moving to another location,

   After the Loma Prieta earthquake, they had to put cribbing under portions of San Francisco's Embaracadero Freeway, for fear it would collapse.

   If the structure is to be raised in place without relocation, once it is raised to the desired elevation the jacks are replaced with timber cribbing. -- US Army Corps of Engineers site

3. The cribbing used to support anything from below or on a side, as with a retaining wall, or to prop up a piece of heavy machinery.
4. A self-injurious tendency of certain horses to swallow air while slobbering and biting onto objects in and about their enclosure and regarded as an equine form of obsessive-compulsive disorder.