noun

• An English and Scottish surname transferred from the given name derived from the given name Alan.
• A male given name from the Celtic languages, a variant of Alan; in modern use often transferred from the surname.
• A number of places in the United States:
• A ghost town in Pima County, Arizona.
• An unincorporated community in Allen County, Indiana.
• A minor city in Lyon County, Kansas.
• A minor city in Floyd County, Kentucky.
• An unincorporated community in Natchitoches Parish, Louisiana.
• An unincorporated community and census-designated place in Wicomico County, Maryland.
• A village in Hillsdale County, Michigan.
• An unincorporated community in Quitman County, Mississippi.
• A village in Dixon County, Nebraska.
• A town in Allegany County, New York.
• A town in Hughes County and Pontotoc County, Oklahoma.
• A census-designated place in Bennett County, South Dakota.
• A city in Collin County, Texas.
• A former unincorporated community in Lincoln County, West Virginia.
• An unincorporated community in Clear Creek, Eau Claire County, Wisconsin.
• A number of townships in the United States, listed under Allen Township.
• A number of rivers in England:
• A river in Dorset, which joins the (Dorset) Stour at Wimborne Minster.
• A river in Northumberland, which joins the South Tyne.
• A river in north Cornwall, which joins the River Camel near Sladesbridge.
• A minor river in south-west Cornwall, which forms the Truro River at Truro.
• A village in County Kildare, Ireland.
• A townland in County Tyrone, Northern Ireland.
• A city in Río Negro province, Argentina.
• A municipality in Northern Samar, Philippines.
• (colloquial) Short for Allen wrench. [(US) A hex head wrench.]