• (a.) Thin-billed; -- applied to birds with a slender bill, as the humming birds.
Ten`u·i·ros'tral adjective (Zoology) Thin-billed; -- applied to birds with a slender bill, as the humming birds. 
tenuirostral, tenuirostres Thin-billed; applied to birds with a slender bill; such as, humming birds.