ceil

To line or finish (a surface, such as a wall), with plaster, stucco, thin boards, or similar.

It is nearly always old and bare, built of rough boards, and neither plastered nor ceiled.

A ceiling.

[…] The mossy sward / Beneath their feet, their carpet was, / An azure ceil, the sky above; […]

Abbreviation of ceiling.

To set a higher bound.