Example sentences
jiān煎liǎng两gè个jī鸡dàn蛋。
Fry two eggs.
jī鸡dàn蛋duō多shao少qián钱？
How much are the eggs?
About this word
鸡 is "chicken" and 蛋 is "egg", so 鸡蛋 is a chicken egg, the default egg in a Chinese kitchen. Chinese names animal products by putting the animal first, the same pattern as 牛奶, 羊肉, 牛肉 and 猪肉. The same 蛋 also covers egg-shaped things, which is why 脸蛋, "face egg", means cheeks. Note that 鸡蛋 is the ingredient you cook with, while 蛋 alone is just "egg"; and chicken as meat is 鸡肉, never 鸡 by itself.
The story behind the character
鸡
鸡 has 鸟 (bird) on the right. The traditional 雞 is 隹, a short-tailed bird, with 奚 giving the sound; the simplification swapped 奚 out for 又. Xu Shen's definition is the best part: 雞，知時畜也, a domestic animal that knows the time. The rooster was the alarm clock, and the character still says so.
蛋
蛋 is 虫 (insect) at the bottom with a sound element stacked on top. It is a late character, too young to be in Xu Shen's dictionary. At first it meant the eggs of birds and turtles, and it spread from there to every egg you eat. 鸡蛋, a chicken's egg, uses the same 蛋 you would use for a duck.