Birr, n. 1. A whirring
sound, as of a spinning wheel.
2. A rush or impetus; force.
Birr (?), v. i. [imp. & p.
p. Birred (?); p. pr. & vb. n.
Birring.] [Cf. OE. bur, bir, wind, storm wind, fr.
Icel. byrr wind. Perh. imitative.] To make, or move with, a
whirring noise, as of wheels in motion.