turris

Tower enters English through Old French tur, from the Latin turris, from the Greek týrris or týrsis. The Greek word may itself be borrowed from a pre-Greek Mediterranean language. Tall structures for observation, defense, and prestige were built independently across civilizations — the ziggurats of Mesopotamia, the pharos of Alexandria, the broch towers of Iron Age Scotland. The need for a tall structure is universal. The word tower attached to the European version.

Roman turres were military structures — watchtowers along roads, siege towers rolled against enemy walls, signal towers along frontiers. Hadrian's Wall in northern England had turrets at regular intervals for observation. The military function was primary: you build tall to see far. Everything else — bells, clocks, prisons, luxury apartments — came later.

Medieval castle towers evolved specific names for specific positions. A corner tower is a flanking tower. A gate tower protects the entrance. A shell keep is a tower on a mound. A barbican is a tower defending the approach. The Tower of London — just 'the Tower' in common speech — is an entire castle complex, but its name comes from the White Tower at its center, the Norman keep that defined the fortress.

The skyscraper is a tower by another name. The Empire State Building, the Burj Khalifa, and every other tall building in every city is a descendant of the same impulse that built the first watchtower: go higher, see further, be seen from further. The word tower has accommodated structures from ten feet to two thousand feet without requiring a new name.