underlay

verb

1. (form-of, past)simple past of underlie
2. (transitive)To lay (something) underneath something else; to put under.
3. (transitive)To provide a support for something; to raise or support by something laid under.

   “to underlay a cut, plate, or the like, for printing”

4. (transitive)To put a tap on (a shoe).
5. (ambitransitive)To incline from the vertical.

noun

1. A layer (of earth, etc.) that lies under another; substratum.
2. A soft floor covering that lies under a carpet.
3. Anything that is underlaid.
4. (historical)A piece of paper pasted under woodcuts, stereotype plates, etc. in a form, to bring them up to the necessary level for printing.
5. Lyrics; or more specifically, the way in which lyrics are assigned to musical notes.

   “The underlay in bar 3 is unclear in Handel's manuscript.”