ˈʌndəɹˌleɪ ʌndəɹˈleɪ

provide with a base, support, lining, or backing underlay the boards with joists put (something) under or beneath They underlaid the shingles with roofing paper raise or support (the level of printing) by inserting a piece of paper or cardboard under the type underlay the plate a pad placed under a carpet