A micropyle's function differs slightly according to whether it is used in botany or zoology. In botany, a micropyle refers to any opening in an ovule's outer layer. This opening allows pollen to fertilize the plant. In zoology, it is a pore in an ovum's membrane.
A micropyle in the ovum's membrane allows a sperm to enter the ovum. In both plants and animals, a micropyle serves as an opening that allows a fertilizing agent to enter and interact with the egg or ovum. The origin of the word can be dated to between 1815 and 1825 and has its roots in the Greek language.