The word "热门" is formed through a vivid conceptual metaphor: it directly combines the character for "热" (rè), meaning "hot" as in temperature, with "门" (mén), meaning "door" or "gate". This creates the mental image of a place or subject that is so intensely popular and sought-after that it metaphorically generates heat from the crowd of people clamoring at its entrance, thus symbolizing a current trend, a popular spot, or a topic of feverish interest.