"The watchtower" translates to Spanish as "la atalaya." Alternative translations include "la torre de observación," "la torre de vigilancia" or "la garita," although this latter term also refers to a gate or sentry box.
Since "torre," "atalaya" and "garita" are all feminine nouns, "the" translates to "la," the feminine form of the definite article. "Atalaya," the most direct translation of "watchtower," has no cognate in English, unlike "torre," which is very similar to the English word "tower." "Atalaya" derives either from the Classical Arabic word "a?-?aláya," which refers to a scouting party that watches an enemy army's movements, or the Classical Arabic word "a?-??li'a," which means "ascending" or "that rises."
Interestingly, the Jehovah's Witnesses publish a monthly magazine titled "The Watchtower." This magazine is translated into 247 languages, including Spanish. The Spanish title of the magazine from 1879 to 1939 was "La Torre del Vigía," an acceptable translation but one that is mostly used in Spain. Therefore, to reflect the magazine's growing presence in Latin America, the Spanish version has been titled "La Atalaya" since 1939, using a more widely accepted translation.
Another example of this translation is found in comic books produced by DC. The Justice League's Watchtower, the base used by Justice League members, is translated in Spanish television adaptations as "La Atalaya de la Liga de la Justicia".