Definition of "yin"

"Steamed fish and chicken and vegetable soup and even mushrooms are considered cooling foods, edible materializations of the yang, the pure primal air. The yin, or earth element, inheres in fried dishes and especially in shark's fin soup. Am I right, Mr Lee?"

1956, Anthony Burgess, Time for a Tiger (The Malayan Trilogy), published 1972, page 187

According to traditional Chinese medicine, blood carries chi, your “life force,” which fuels all the functions of the body. When you lose blood, you lose chi, and this causes your body to go into a state of yin (cold). When yin (cold) and yang (hot) are out of balance, your body will suffer physical disorders.

2017 January 8, Leslie Hsu Oh, “I tried the Chinese practice of ‘sitting the month’ after childbirth”, in The Washington Post‎, archived from the original on 08 January 2017, Health & Science‎