Apportionment: The process of dividing the 435 seats, in the House of Representatives, among the 50 states based on population.

Census Block: The smallest of all geographic areas. A group of blocks make up a census tract. Blocks typically follow streets or other physical features. Blocks average about 100 people each.

Census Tract: Counties are subdivided into census tracts. Tracts remain fairly constant from census to census. Census tracts average about 4,000 people.

Congressional District: The United States House of Representatives is made up of 435 Congressional Districts or seats. These elected officials represent you in Washington DC. In 2012, Washington State will have 10 congressional districts.

County Council District: Pierce County is made up of seven council districts. One council person is elected from each district. These elected officials represent you at the County level.

GIS: Geographical Information System. A computer database application used to provide geographic information in both a spatial and tabular format.

Legislative District: Washington State is made up of 49 Legislative Districts. Two representatives and one senator is elected from each Legislative District. These elected officials represent you at the state level.

Precinct: A geographic subdivision created for voting purposes. Vote totals are reported by precinct. A precinct is made up of census blocks.

TIGER: Topologically Integrated Geographic Encoding and Referencing system.