Answer:
Patrician: A person of higher socioeconomic status (think noblemen, people of status).
Legion: A large group of Roman soldiers (a few thousand).
Aqueduct: A set of systems that the Romans used to transfer water from location to location. Famous ones look like large, arched bridges stacked on top of one another.
Forum: A public space in the middle of Roman government buildings. These were used for whatever important daily things were happening - breaking news, election speeches, etc.
You could just search these online, for the future.