Sino-Korean vocabulary

Sino-Korean vocabulary or Hanja () refers to Korean words of Chinese origin. Sino-Korean vocabulary includes words borrowed directly from Chinese, as well as new Korean words created from Chinese characters. These terms are probably borrowed during the era of Literary Chinese in Korea. About 60 percent of Korean words are of Chinese origin; however, the percentage of Sino-Korean words in modern usage is estimated to be lower. Many words are often truncated, or altered and treated as native to the Korean language. 
History.
The use of Chinese and Chinese characters in Korea dates back to at least 194 BCE. While Sino-Korean words were widely used during the Three Kingdoms period, they became even more popular during the Silla period. During this time, male aristocrats changed their given names to Sino-Korean names. Additionally, the government changed all official titles and place names in the country to Sino-Korean.
Sino-Korean words remained popular during the Goryeo and Joseon periods. However, Sino-Korean vocabulary has continued to grow in South Korea, where the meanings of Chinese characters are used to produce new words in Korean that do not exist in Chinese. By contrast, North Korean policy has called for many Sino-Korean words to be replaced by native Korean terms.
Usage.
Sino-Korean words constitute about 60 percent of South Korean vocabulary, the remainder being native Korean words and loanwords from other languages, mostly English. Sino-Korean words are typically used in formal or literary contexts, and to express abstract or complex ideas. Almost all Korean surnames and most Korean given names are Sino-Korean. Additionally, Korean numerals can be expressed with Sino-Korean and native Korean words, though each set of numerals has different purposes.
Sino-Korean words may be written either in the Korean alphabet, known as Hangul, or in Chinese characters, known as Hanja.
Examples.
Words borrowed from Chinese.
Sino-Korean words borrowed directly from Chinese come mainly from Chinese classics, literature, and colloquial Chinese.
Words created from Chinese.
These Chinese words below are created in Korea. They are not used in China, Japan nor Vietnam.
Words borrowed from Sino-Japanese.
Sino-Korean words borrowed from Sino-Japanese are used only in Korean and Japanese, not in Chinese.