Lewis Short
(verb) : observĭto, āvi, observo
* To watch carefully, to note, observe (class.): Assyrii.. trajectiones motusque stellarum observitaverunt,Cic. Div. 1, 1, 2: deorum voces,id. ib. 1, 45, 102: omnia,App. Deo Socr. p. 52, 31; id. M. 8, p. 208, 17: caerimonias, Massur. Sabin. ap. Gell. 10, 15, 26.
Charlton T. Lewis, Charles Short, A Latin Dictionary