Twenty-foot Equivalent Unit. A container that is 20 feet long is 1 TEU while a 40 foot container unit is 2 TEU. A 53 foot container is 2.65 TEUs

a unit of length, 1/12 foot, equivalent to 2.54 centimeters

A foot is a unit of length, equivalent to 0.3048 meters.

A unit of sound absorption for a surface, equivalent to 1 square foot (0.09290304 square meter) of perfectly absorbing surface. Also known as absorption unit; open window unit (OW unit); square-foot unit of absorption.

FEU is Forty Feet Equivalent Unit & TEU is Twenty Feet Equivalent Unit. these are a type of containers used in the logistics.