Or, if you're looking for a definition for the word 'this', then here:
THIS pronoun pronoun: this; pronoun: these 1. used to identify a specific person или thing close at hand или being indicated или experienced. "is this your bag?" -used to introduce someone или something. "this is the captain speaking" -referring to the nearer of two things close to the speaker (the other, if specified, being identified by “that”). "this is different from that" 2. referring to a specific thing или situation just mentioned. "the company was transformed, and Ward had played a vital role in bringing this about"
determiner determiner: this; determiner: these 1. used to identify a specific person или thing close at hand или being indicated или experienced. "don't listen to this guy" -referring to the nearer of two things close to the speaker (the other, if specified, being identified by “that”). "this one или that one?" 2. referring to a specific thing или situation just mentioned. "there was a court case resulting from this incident" 3. used with periods of time related to the present. "I thought Ты were busy all this week" referring to a period of time that has just passed. "I haven't left my постель, кровати these three days" 4. informal -used (chiefly in narrative) to refer to a person или thing previously unspecified. "I turned around, and there was this big mummy standing Далее to us!"
adverb adverb: this 1. to the degree или extent indicated. "they can't handle a job this big"
