Meaning

noun a pad placed under a carpet

verb raise or support (the level of printing) by inserting a piece of paper or cardboard under the type

verb put (something) under or beneath

originFrom Middle English underleyen, from Old English underleċġan (“to underlay, prop, support”), equivalent to under- + lay. Cognate with Dutch onderleggen (“to lay or put under”), German unterlegen (“to underlay”), Swedish underlägga (“to underlay”).

Etymology from Wiktionary, CC BY-SA 3.0