Jia-jie 假借

pronounced as: J'ya J'yeah
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Jia-jie (假借) is one of the “liu shu” (lit. six scripts; 六书; pronunciation: lyou shoo) or the six Chinese hanzi character classifications. Jia-jie characters reflect how the Chinese language has evolved to adapt to socio-cultural changes over time.

• Historically, when a new concept emerged and it couldn’t be expressed with the current vocabulary, an existing character would be assigned to represent this new idea. As a result, an individual hanzi character often have multiple distinctively different definitions.
• Sometimes, the more recent meaning of a certain character can replace its original meaning completely; consequently, a brand new character would be created to represent the abandoned origin meaning.​ ​

Reference: 

1. Cao, Bohan 曹伯韩. Guo xue chang shi 国学常识 [Elementary knowledge of Sinology]. 1947. Reprint, Beijing: dangdai shijie chubanshe [Dang-Dai Shi-Jie Publishing] 当代世界出版社, 2013.