In staggered elections, not all places in an elected body are up for election at the same time. The staggered election keeps some continuity in the elected body.

For example United States Senators have a 6-year term but they are not all elected at the same time. Rather, every two years elections are held for one third of US Senate seats

Classes of United States Senators

The three classes of United States Senators are currently made up of 33 or 34 Senate seats. The purpose of the classes is to determine which Senate seats will be up for election in a given year. The three groups are staggered so that one of them is up for election every two years.A senator's...

. Elections to the Senates of several other countries, and to regional bodies, are similarly staggered.

Staggered elections should not be confused with rolling election

Rolling election

Rolling elections are elections in which all representatives in a body are reelected, but these elections are spread over a period of time rather than all at once. Examples are the presidential primaries in the United States, and, due to logistics, general elections in Lebanon and India...

.