underlayˈ transitive verb (pat and pap underlaidˈ)

1. To support or provide with something laid under
2. To lay under
3. To put down, surpass (Spenser)
4. Often used erroneously for underlie below, of which it is the pat

To slope away from the vertical, to hade

Something laid under, eg felt or rubber to help preserve a carpet, or (printing) a piece of paper, etc, pasted under to bring to type-height