Proper noun
(historical) The tripartite division of China between the states of Wei (魏 (Wèi)), Shu (蜀 (Shǔ)), and Wu (吳／吴 (Wú)), during AD 220–280, following the Han dynasty and preceding the Jin dynasty.
(historical) The tripartite division of Korea between the kingdoms of Goguryeo (고구려(高句麗) (goguryeo)), Baekje (백제(百濟) (baekje)), and Silla (신라(新羅) (silla)), around 57 BC to AD 668, prior to its unification under Silla.
Source: en.wiktionary.orgGod had sifted three kingdoms to find the wheat for this planting. Henry Wadsworth Longfellow
Besides, historical accounts of the Three Kingdoms era had several specific records of Guan Yu thrusting his opponents down (probably with a spear-like polearm) in battles, instead of cutting them down with a curved-blade. Source: Internet
Burbank and Cooper (2010), 51. After the fall of the Han Dynasty, the nine-rank system was established during the Three Kingdoms period. Source: Internet
Especially during the Three Kingdoms of Korea period, in which wars among the Korean states, as well as with neighboring Chinese dynasties, were highly frequent, Korean military forces were constantly improving upon weaponry and martial practices. Source: Internet
"Great Emperor of Wu"), was the founder of the state of Eastern Wu during the Three Kingdoms period. Source: Internet
In the collectible card game Magic: The Gathering there is a card named "Sun Quan, Lord of Wu", in the Portal Three Kingdoms set. Source: Internet