to perceive (a thing or a person) to be something or somebody previously known or encountered
to perceive (something) clearly
He recognized his own inadequacy
to acknowledge the admit (something or somebody) as being of a particular status or having validity of
They recognized her as legitimate representative
to acknowledge the de facto existence or the independence of (e.g. a government or state)
to admit that (something) is a fact
He recognizes his obligation
to show appreciation of (something or somebody), e.g. by praise or reward
Her bravery was recognized by a special award
said of somebody chairing a meeting: to allow (somebody) to speak
said of e.g. of a computer: to be able to identify correctly and deal with (e.g. a printed character)