A shack is a type of small, often primitive shelter or dwelling. The word may derive from the Nahuatl (Aztec) word xahcalli or “adobe house” by way of Mexican Spanish xacal/jacal, which has the same meaning as “shack”. It was a common usage among people of Mexican ancestry throughout the U.S. southwest and was picked up by speakers of American English.
An alternative etymology is that shack derives from teach, pronounced chaċ, meaning “house” in Irish Gaelic, which was absorbed into American English from the 1880s onwards. Similarly shanty may have derived from the Gaelic seantigh, prounced shan-tí, meaning “old house”, at a time when Irish migrants lived in New York’s tenements.
It is possible that up to a billion people worldwide live in shacks. Fire is a significant hazard in tight-knit shack settlements. Shack settlements are also sometimes known as slums or shanty towns.
In amateur radio jargon, a shack refers to the place where an amateur radio operator’s radio sending and receiving apparatus is located and operated. The term originally meant that part of a ship where the radio apparatus was located and operated. This is the inspiration for the name ‘RadioShack’.
In military aviation jargon, a “shack” refers to a successful, direct hit on a ground target.
Bus stops are often referred to as “shacks” by commuters and the common passerby because some bus stops have roofs on top of the stops for shade and protection from the rain.