Underlay - Definition

n 1: a pad placed under a carpet [syn: carpet pad, rug pad,
underlay, underlayment]
v 1: raise or support (the level of printing) by inserting a
piece of paper or cardboard under the type; "underlay the
plate"
2: put (something) under or beneath; "They underlaid the
shingles with roofing paper"
3: provide with a base, support, lining, or backing; "underlay
the boards with joists"