Chief means the leader or most important person in a group or organization. A fire chief leads the firefighters, making decisions about how to fight fires and keep the community safe. A chief executive officer (CEO) runs a company, setting its direction and making major decisions. Some Native American tribes have chiefs who guide their communities and preserve their traditions.

The word also describes something that's most important or primary. Your chief concern before a test might be remembering all the formulas. A detective's chief suspect is the person most likely to have committed the crime. When you have a chief reason for doing something, that's your main motivation, even if you have other smaller reasons too.

You'll see it combined with other words to show someone's role: editor-in-chief (the top editor), commander-in-chief (the highest military commander), or chief justice (the leader of a court).