A small opening or depression similar to a navel, as the hollow at the base of the shell of some gastropod mollusks, one of the openings in the shaft of a feather, or the hilum of a seed.

• 脐和肚脐相似的小开口或凹陷，如某些腹足纲软体动物壳的底部的洞，羽毛管的开口中的一个，或种子的种脐