The four mythological creatures in Chinese astronomy that guard the four directions, namely the Azure Dragon 青龙 qīng​lóng (East), White Tiger 白虎 bái​hǔ (West), Vermilion Bird 朱雀 zhū​què (South), and Black Tortoise 玄武 xuán​wǔ (North); also known as the 四灵 sì​líng or 四神 sì​shén

The four combinations of two yin/yang lines (Old Yang, Young Yang, Old Yin, Young Yin) in the 易经 yì​jīng, often associated with the four seasons

The four elements metal, wood, water, and fire

Collective term for the sun, moon, stars, and planets

The four primary methods of creating Chinese characters, namely pictograms, simple ideograms, compound ideograms, and phono-semantic compounds

The guardian deities of Daoist temple gates, corresponding to the four mythological creatures (Azure Dragon, White Tiger, Vermilion Bird, and Black Tortoise)

The four types of images or signs in the 易经 yì​jīng: real images, false images (假象 jiǎ​xiàng), meaningful images, and functional images