City councils generally consist of several (usually somewhere between 5 and 50, depending on the city's size) elected aldermen or councillors, and a mayor. In larger cities the council may elect other executive positions as well, such as a council president and speaker.
The council generally functions as a parliamentary or congressional style legislative body, proposing bills, holding votes, and passing laws to help govern the city.
The role of the mayor in the council varies depending on whether or not the city uses council-manager government or mayor-council government.