What word means the body of citizens?

The word that means the body of citizens, on the USCIS reading vocabulary list, is Public. The public, in civic usage, refers to the people of a community, state, or country considered collectively, and the word also functions as an adjective meaning open to or shared by all members of a community.

American civic life is full of institutions and concepts framed in terms of the public. Public officials are the men and women who hold elected or appointed positions in government and who serve the public interest. Public service is work undertaken to benefit the public good, whether through government employment, military service, or volunteer civic engagement.

Public schools, free and open to all eligible students under state laws and the Equal Protection Clause of the Fourteenth Amendment, are funded primarily through state and local taxes. Public lands, including national parks, national forests, and Bureau of Land Management lands, are owned by the federal government and managed for the use and enjoyment of all Americans. Public health agencies, including the Centers for Disease Control and Prevention and state and local health departments, protect the population from disease.

Public broadcasting, including the Corporation for Public Broadcasting, PBS, and NPR, provides noncommercial educational content. The word public also appears in important constitutional phrases: the Sixth Amendment guarantees the right to a public trial, ensuring that criminal proceedings happen in open court rather than in secret; and the Fifth Amendment's Takings Clause requires just compensation when private property is taken for public use.

On the reading test Public may appear in a sentence about public schools, public officials, or the public good.