1. (noun)tower a structure taller than its diameter; can stand alone or be attached to a larger building
2. (noun)column, tower, pillar anything that approximates the shape of a column or tower "the test tube held a column of white powder"; "a tower of dust rose above the horizon"; "a thin pillar of smoke betrayed their campsite"
3. (noun)tugboat, tug, towboat, tower a powerful smallboat designed to pull or push larger ships
4. (verb)loom, tower, predominate, hulk appear very large or occupy a commanding position "The huge sculpture predominates over the fountain"; "Large shadows loomed on the canyon wall"