A jailer is a person whose job is to guard prisoners and manage a jail. The jailer makes sure people locked up in jail stay secure, follow the rules, and receive their meals. In colonial America and medieval times, the jailer often lived right at the jail with their family, keeping watch day and night.

In old stories and historical accounts, jailers sometimes appear as harsh figures who treated prisoners roughly, but modern jailers, usually called corrections officers or jail guards today, are trained professionals responsible for safety and security.

You might encounter the word jailer most often in historical fiction or when reading about the past. In The Count of Monte Cristo, the jailer brings the imprisoned hero his daily bread. In American history, jailers held everyone from common thieves to people like Paul Revere, who was briefly jailed by the British during the Revolutionary War.

The spelling jailer is more common in American English, while British English often uses gaoler, though both words sound the same when spoken aloud.