The verb expand means to make something bigger or wider. It might refer to something concrete, as when you blow into a balloon and make it expand, or something more abstract, as when you study to expand your mind.
Expand is a combination of the Latin words ex-, meaning "out," and pandere, "to spread." The idea of spreading out was always there, though the current idea of something actually becoming larger was first recorded in the mid-17th century. Expand is a versatile word that can refer to anything getting bigger, from a nation's growing influence in a neighboring country to a waistline that needs a larger belt.