tower (n.1) Look up tower at Dictionary.com
Old English torr "tower, watchtower," from Latin turris "a tower, citadel, high structure" (also source of Old French tor, 11c.; Spanish, Italian torre "tower"), possibly from a pre-Indo-European Mediterranean language. Meaning "lofty pile or mass" is recorded from mid-14c. Also borrowed separately 13c. as tour, from Old French tur; the modern spelling (1520s) represents a merger of the two forms.
tower (n.2) Look up tower at Dictionary.com
"one who tows," 1610s, agent noun from tow (v.).
tower (v.) Look up tower at Dictionary.com
c. 1400, "rise high" (implied in towered); see tower (n.). Also, of hawks, "to fly high so as to swoop down on prey" (1590s). Related: Towering.