recon

"preliminary examination or survey," specifically "an examination of a territory or enemy position with a view to directing military operations," 1810, a word from the Napoleonic Wars, from French reconnaissance "act of surveying," literally "recognition," from Old French reconoissance "recognition, acknowledgement" (see recognizance).

also reconnoitre, 1707, "make a survey," specifically "to examine a tract or region for military or engineering purposes," from older French reconnoitre (Modern French reconnaître), from Old French reconoistre "to identify" (see recognize). Related: Reconnoitering.

1941, World War II military slang, short for reconnaissance (n.). As a verb by 1943. The World War I military slang term for the noun was recco (1917). Also compare recon.