Webster's Revised Unabridged Dictionary · 1913

Chirrup

Chirrup , transitive verb

[See Chirp.]

To quicken or animate by chirping; to cherup.

Chirrup , intransitive verb

To chirp. — Tennyson
The criket chirrups on the hearth. — Goldsmith

Chirrup , noun

The act of chirping; a chirp.
The sparrows' chirrup on the roof. — Tennyson