The meaning of the given terms are as follows: 1. Apiary - a place where bees are kept. 2. Aviary - a large cage or area in which birds are kept. 3. Plutocracy - a government formed by wealthy people. 4. Aquarium - a glass container filled with water, in which fish and water animals are kept. All options except "Plutocracy", are the terms denotes places, while Plutocracy is a form of government. Hence, "Plutocracy" is the odd one.