Captivity:the situation in which a person or animal is kept somewhere and is not allowed to leave
Noun/A lion in the zoo is in captivity.
Creature:any large or small living thing that can move independently
Noun/I saw a strange creature in my yard.
Zoo: a place where there are a lot of people and their behaviour is not well organized or controlled
Noun/I went to the zoo last week and I had a lot of fun.