(used to indicate a person, thing, idea, state, event, time, remark, etc., as pointed out or present, mentioned before, supposed to be understood, or by way of emphasis): That is her mother. After that we saw each other.
(used to indicate one of two or more persons, things, etc., already mentioned, referring to the one more remote in place, time, or thought; opposed to this): This is my sister and that's my cousin.
(used to indicate one of two or more persons, things, etc., already mentioned, implying a contrast or contradistinction; opposed to this): This suit fits better than that.
(used as the subject or object of a relative clause, especially one defining or restricting the antecedent, sometimes replaceable by who, whom, or which): the horse that he bought.
(used as the object of a preposition, with the preposition standing at the end of a relative clause): the farm that I spoke of.