The word "寒暄" is formed by combining the character "寒" (hán), meaning "cold", with "暄" (xuān), meaning "warm". These two characters directly reference opposite weather conditions, and their juxtaposition creates a compound that literally signifies "cold and warm". This literal meaning is used metaphorically to represent the exchange of polite greetings or small talk about topics like the weather, thereby forming the term for social niceties.