zealot – One who espouses a cause or pursues an object in an immoderately partisan manner.
zeitgeist – The intellectual and moral tendencies that characterize any age or epoch.
zenith – The culminating-point of prosperity, influence, or greatness.
zephyr – Any soft, gentle wind.
zodiac – An imaginary belt encircling the heavens within which are the larger planets
zero – – the number meaning none or nothing
zoo – – a place where animals are kept for the public to look at and study