Number + 脚 + Noun
脚 (jiǎo) primarily means "foot" or "leg" and can function as an informal measure word describing animals by the number of their feet. In contexts like 三脚恐龙 (three-footed dinosaur), 脚 acts as a classifier indicating how many feet the creature has. This usage is specific to descriptive or scientific contexts.
那只猫只有三脚,但跑得很快。
nà zhī māo zhǐyǒu sān jiǎo, dàn pǎo de hěn kuài.
That cat only has three legs, but it runs very fast.
传说中有一种三脚蟾蜍能带来好运。
chuánshuō zhōng yǒu yī zhǒng sān jiǎo chánchú néng dàilái hǎoyùn.
Legend has it that a three-legged toad can bring good luck.
这张桌子是四脚的,很稳。
zhè zhāng zhuōzi shì sì jiǎo de, hěn wěn.
This table has four legs and is very stable.