The word "油炸" is formed by combining the character "油" (yóu), meaning "oil", with the character "炸" (zhá), meaning "to fry" or "deep-fry". This creates a compound word where the first character specifies the medium used in the action described by the second character, resulting in a term that literally means "oil-fry" and refers specifically to the method of cooking food by submerging it in hot oil.