That part of a masonry wall behind the exterior facing.

Overflow in a drain or piping system, due to stoppage.

1. Logical or physical facilities to aid the process of restarting a computer system and recovering the information in it following a failure.

2. The provision of such facilities.

1. An item under development intended to perform the same general functions that another item also under development performs.

2. A compressible material used behind a sealant to reduce its depth and to support the sealant against sag or indentation.

1. An image printed on the reverse side of a printed sheet.

2. The printing of such an image.

A support used to balance the upsetting force in the workpieces during flash welding.

During drilling, the holding of one section of pipe while another is screwed out of it or into it.