• 鶏卵けいらん — hen’s egg
• 魚卵ぎょらん — fish egg / roe
• 卵黄らんおう — egg yolk
• 卵白らんぱく — egg white
• 卵生らんせい — oviparity

卵 is traditionally explained as pictographic, linked to images of eggs (often fish eggs in early forms). It now broadly covers eggs in biology and food contexts.

卵たまごを 三個さんこ 買かいました。
I bought three eggs.

この卵黄らんおうは とても濃こい 黄身きみで、味あじも 濃厚のうこうです。
This yolk is very rich in color, and the taste is rich, too.