Why is the ninth month called September?
"in addition, in excess," late Old English, stressed variant of Old English prep. to "in the direction of, furthermore" (see to). The spelling with -oo is first recorded 1590. Use after a verb, for emphasis (e.g. did, too!) is attested from 1914. German zu unites the senses of English to and too. Slang too-too "excessive in social elegance" first recorded 1881. Too much "excellent" first recorded 1937 in jazz slang.