Lewis & Short

vīmĭnālis, e, adj. [vimen], of or belonging to osiers.

  1. I. In gen.: salix, bearing twigs for plaiting, Col. 4, 30, 2; Plin. 17, 20, 32, § 143.
  2. II. Adj. propr.: Viminalis Collis, one of the seven hills of Rome (Liv. 1, 44), so named from a willow-copse which stood there; whence, also, the Jupiter there worshipped was called Vīmĭnĭus, Varr. L. L. 5, § 51 Müll.; Front. Aquaed. 1, 19; Plin. 17, 1, 1, § 2; Fest. p. 376 Müll.
    The gate leading to it was called Viminalis Porta, Fest. l. l.; Front. Aquaed. 1, 19.