adv. Mus. [It. tranquillo adj. TRANQUIL.] In a tranquil style or tempo; tranquilly.
1854. J. Schuberths Mus. Hand-bk. (ed. 4), Tranquillamente, Tranquillo, calmly, peacefully, tranquil.
1889. Grove, Dict. Mus., Tranquillo, an Italian term, meaning calmly, quietly.
1905. Westm. Gaz., 22 April, 12/1. Resting wilt thou Largo play, Presto or Tranquillo?