UFO (also ufo)

abbr 缩写 = (pl ~s) unidentifiedflying object (esp a flying saucer) 不明飞行物（尤指飞碟）.

tyrant, tyrany, tyre, tyre (US tire), tyro, tzar, U, U, u, U-boat, U-turn, UAE, UAR, ubiquitous, ubiquity, UCCA, UDA, udder, UDI, UDR, UEFA, ugh, ugli, ugliest, ugliness, ugly, ugly-looking, UHF, UHT, UK, ukulele, ulcer, ulcerate, ulceration, ulcerous, ulna, ulterior, ultimate, ultimately, ultimatum, ultimo,