Tall tale and Urban legend

Tall tale noun - An improbable (unusual or incredible or fanciful) story.

Urban legend and tall tale are semantically related. In some cases you can use "Urban legend" instead a noun phrase "Tall tale".

Urban legend noun - A story that appears mysteriously and spreads spontaneously in various forms and is usually false; contains elements of humor or horror and is popularly believed to be true.

Tall tale and urban legend are semantically related. Sometimes you can use "Tall tale" instead a noun phrase "Urban legend".