Definitions of tower:

• noun:   a structure taller than its diameter; can stand alone or be attached to a larger building
• noun:   anything tall and thin approximating the shape of a column or tower

  Example: "A tower of dust rose above the horizon"

• noun:   a powerful small boat designed to pull or push larger ships
• verb:   appear very large or occupy a commanding position
• name:  A surname (rare: 1 in 50000 families; popularity rank in the U.S.: #5077)