-idium, -idion

(Greek: smaller or lesser; little)

acarinarium (s) (noun), acarinaria; acarinariums (pl)
A specialized anatomical structure which is adapted to facilitate the retention of mites on the body of an organism, such as a bee or a wasp: The acarinarium evolved to enhance the mutual relationship between the mites and the host organisms.
androgametangium (antheridium [s], antheridia [pl])
1. A male reproductive structure producing gametes, occurring in ferns, mosses, fungi, and algae.
2. The male sex organ of spore-producing plants; produces antherozoids; equivalent to the anther in flowers.
antheridium, antherid
The male sex organ of the lower plants, usually producing numerous motile, flagellate gametes (antherozoids).
arachnidium (s) (noun), arachnidia (pl)
The glandular organ in which the material for the web of spiders is secreted: The arachnidium is the spinning apparatus of a spider, including the spinning glands and spinnerets.
ascidium (s), ascidia (pl); ascidiform
1. A part of a plant or fungus shaped like a pitcher or bag.
2. A pitcher-shaped, bottle-shaped, or baglike part or organ; such as, the hollow tubular leaf of a pitcher plant.
The rhizomes and stipes of Dryopteris filix-mus (European aspidium or male fern), or of Dryopteris marginalis (American aspidium or marginal fern) (family Polypodiaceae); used in the treatment of tapeworm infestation, usually in the form of the oleoresin or extract, but because of its potential toxicity, its use is restricted to patients who do not respond to treatment with safer drugs such as dichlorophen, niclosamide, or quinacrine.
conidium (s) (noun), conidia (pl)
1. A fungal spore: Conidia are always present in the air, but their levels fluctuate from day to day depending on the seasons.
2. Etymology: from Greek konis, "dust".
A water-borne protozoan parasite that contaminates drinking water supplies, causing intestinal infections in human beings and domestic animals.
ctenidium (s) (noun), ctenidia (pl)
1. A respiratory or breathing organ or gill which is found in many mollusks: The cenidium is a structure which exists in bivalves and in many aquatic gastropods; such as, some freshwater snails and sea snails and also in some sea slugs.

Some aquatic gastropods possess one ctenidium while others have a pair of ctenidia.

A ctenidium is shaped like a comb or a feather, with a central part from which many filaments or plate-like structures protrude which are lined up in a row.

2. Etymology: The word is Latinized but is derived from the Greek ktenidion which means "little comb".
The part of a heterobasidium which bears sterigmata and is separated by a septum from the hypobasidium.
hesperidium (s), hesperidia (pl)
A berry having a thickened leathery rind and juicy pulp divided into segments, as an orange or other citrus fruit.
1. Iridium, Ir 192, an artificial radioactive isotope with a half-life of 75 days, used in radiotherapy.
2. A very hard and brittle, exceptionally corrosion-resistant, whitish-yellow metallic element occurring in platinum ores and used principally to harden platinum and in high-temperature materials, electrical contacts, and wear-resistant bearings.
3. Etymology: from 1804, Modern Latin, coined by its discoverer, English chemist Smithson Tennant (1761-1815) from Greek iris, "rainbow"; so called for the varying color of its compounds.

More information is located at Chemical Element: iridium.

nephridium (singular)
A free swimming, ciliated larval stage of a fluke.