underlay

noun

The underlay provides a smooth surface for the carpet.

意味（1）

A layer (of earth, etc.) that lies under another; substratum.

意味（2）

A soft floor covering that lies under a carpet.

意味（3）

Anything that is underlaid.

意味（4）

意味（5）

(music) 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.