too (adv.) Look up too at Dictionary.com
"in addition, in excess," late Old English, stressed variant of Old English preposition to "in the direction of, furthermore" (see to). The spelling with -oo is from late 16c. Use after a verb, for emphasis (as in 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 is from 1530s as "more than can be endured;" sense of "excellent" first recorded 1937 in jazz slang.