Those words are pronouns; words that take the place of a specific person, place, or thing.
The term for a word with similar meaning is a synonym.
I find that the best way is to cut a piece of paper into little squares, and write each letter of the word on a different square. That way you can easily visualize how the letters can be rearranged,...
A dictionary includes the pronunciation of the word and the meaning(s) of the word. It may also include synonyms and antonyms for the word.
A synonym.