Back?
that pron.
1.Used to refer to the one designated, implied, mentioned, or understood.
2.Used to refer to the one, thing, or type specified as follows.
3.Used to refer to the event, action, or time just mentioned.
4.Used to indicate the farther or less immediate one.
5.Used to emphasize the idea of a previously expressed word or phrase.
6.The one, kind, or thing; something.
7.those Used to indicate an unspecified number of people.
8.Used as a relative pronoun to introduce a clause, especially a restrictive clause.
9.In, on, by, or with which.
10.According to what; insofar as.