autoimmune

The term 'autoimmune' is a modern scientific compound, constructed in the early 20th century from two classical roots. The first element, 'auto-', derives from the ancient Greek word for 'self', establishing the core concept of an action directed inward. The second element, 'immune', originates from the Latin immunis, which described a legal exemption from duties or taxes, a sense of being protected or free. In medical Latin, this evolved to signify biological protection from disease. Thus, the literal logic of 'autoimmune' is a state where the body's protective system, which should grant 'exemption' from external threats, mistakenly targets and attacks the 'self', leading to disease.

Structure: auto (self) + immune (resistant) - auto: From Greek autos (αὐτός), meaning "self". In this word, it functions as a combining form meaning "self; same". - immune: From Latin immunis, meaning "exempt from public service, free". In this word, it functions as the base, meaning "resistant to a particular infection or toxin".