(Latin: a suffix; result of, the act of, means of)

1. A cavity or hollow within a bone.
2. A normal dilatation within certain hollow organs; such as, the pyloric end of the stomach.
3. A general term for cavity or chamber which may have specific meaning in reference to certain organs or sites in the body.

The antrum of the stomach (gastric antrum) is a portion before the outlet which is lined by mucosa which does not produce acid. The paranasal sinuses can be referred to as the frontal antrum, ethmoid antrum, and maxillary antrum.

auscultoplectrum (s) (noun), auscultoplectrums (pl)
An instrument for use in both auscultation and percussion of bodily examinations: Dr. Timothy wanted to use an auscultoplectrum in order to listen to Sam's heart and then be able to make a diagnosis.
1. A natural or artificial alloy of gold with at least 20% silver, used to make the first known coins in the Western world.
2. Etymology: from Latin electrum, "amber"; from which the term electron is derived.
lustrum (s) (noun); lustrums, lustra (pl)
1. The historical ceremony of purification or ritual cleansing of the Roman population typically done every five years following a census: The description of the lustrum was accurately recorded in the ancient texts that were discovered in the ruined temple.
2. Etymology: from Latin, "purification"; probably ultimately from an Indo-European word meaning "light, bright".
monstrum (s) (noun), monstra (pl)
In medicine, a horribly deformed person.
plectrum (s), plectra (pl)
1. A small flat pointed piece of plastic, or other material; used for plucking or strumming the strings of a guitar or similar instrument.
2. A small thin piece of metal, plastic, bone, or similar material, used to pluck the strings of certain instruments, such as the zither or lute.
1. A beak-like, or a beak-shaped part, of an organism projection of the anterior part of the head of certain insects; such as, weevils.
2. A platform raised above the surrounding level to give prominence to the person on it.
3. The beak-shaped prow of an ancient Roman ship, especially a war galley.
4. Etymology: from Latin rostrum, name of the platform stand for public speakers in the Forum in ancient Rome.

It was decorated with the beaks of ships taken in the first naval victory of the Roman republic, over Antium, in 338 B.C., and the word's older sense is "end of a ship's prow"; literally, "beak, muzzle, snout"; originally, "means of gnawing" instrument, a noun form of rodere "to gnaw".

sequestrum (s) (noun), sequestra (pl)
A piece of deteriorating bone that has become disconnected during the process of necrosis from a sound bone: When Shanna was walking on the icy street, she slipped and broke her arm and it became necessary that a surgeon remove the sequestrum before she would lose her entire arm.