say it: ree-KAH-nuh-suhns
reconnaissance is a noun meaning "the act of reconnoitring (especially to gain information about an enemy or potential enemy)". It carries one recorded sense.
the act of reconnoitring (especially to gain information about an enemy or potential enemy)
“an exchange of fire occurred on a reconnaissance mission”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for reconnaissance come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.