The word 螃蟹 (pángxiè) for "crab" is formed through a process of semantic compounding where both characters share the same "insect/creature" radical (虫), visually signaling it is an animal. The first character, 螃, acts primarily as a phonetic hint for the word's sound, while the second character, 蟹, carries the core meaning related specifically to crab-like creatures, with its lower component possibly alluding to the creature's hard shell or prying claws. Together, they create a single, fixed unit that uniquely names this particular crustacean.