Lewis Short
(verb) : ūrīnor, āri, (ante-class. collat. form ūrīno, āre) [urina; Gr. οὐρέω]
* To plunge under water, to dive: urinare est mergi in aquam,Varr. L. L. 5, § 126 Müll.; Cic. Fragm. ap. Non. 474, 27; Plin. 11, 37, 72, § 188.—Part.: urinantes,Plin. 9 30, 48, § 91.
Charlton T. Lewis, Charles Short, A Latin Dictionary