In botany, the hilum is a scar or mark left on a seed coat by the former attachment to the ovary wall or to the funiculus

Ovule

Ovule means "small egg". In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: The integument forming its outer layer, the nucellus , and the megaspore-derived female gametophyte in its center...

 (which in turn attaches to the ovary wall). On a bean

Bean

Bean is a common name for large plant seeds of several genera of the family Fabaceae used for human food or animal feed....

 seed, the hilum is called the "eye".

For some species of fungi, the hilum is the microscopic indentation left on a spore

Spore

In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

 when it separates from the sterigma

Sterigma

thumb|right|The sterigmata is the slender extension that connects the spore to the basidia .A sterigma is an extension of the basidium consisting of a basal filamentous part and a slender projection with a spore at the tip...

 of the basidium

Basidium

thumb|right|500px|Schematic showing a basidiomycete mushroom, gill structure, and spore-bearing basidia on the gill margins.A basidium is a microscopic, spore-producing structure found on the hymenophore of fruiting bodies of basidiomycete fungi. The presence of basidia is one of the main...

.

The adjectival form hilar denotes the presence of such a mark, and can be used as a distinguishing characteristic of a seed

Seed

A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...

 or spore

Spore

In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

.