(Greek: around, enclosing, surrounding, about, near, close; often used as a prefix)

Consisting of mucous membrane and periosteum.
1. Periosteum (a dense membrane composed of fibrous connective tissue that closely wraps (invests) all of the bones) having a mucous surface, as in parts of the auditory apparatus.
2. Periosteum that has a mucous surface; or mucous and periosteal surfaces combined to form a membrane.
oxyperitoneum (s) (noun), oxyperitoneums; oxyperitonea (pl)
The introduction of oxygen into the peritoneal cavity: Oxyperitoneum is described as being the addition of oxygen into the membrane lining of the walls of the abdomen.
Inflammation of the peritoneum lining the pelvic cavity.
periadenitis (s) (noun) (no pl)
Inflammation of the tissues surrounding or around a gland: While Jill was at the doctor's office for an examination, Dr. Dawson discovered a case of periadenitis pertaining to the swelling and soreness encircling one of her glands.
periadventitial (adjective) (not comparable)
In anatomy, a reference to the area around the "tunica adventitia" of a blood vessel: In the lecture, the students were informed about the periadventitial veins and arteries in a person's body.

The adventitia is the outermost connective tissue covering any organ, vessel, or other structure not covered by a serosa. The covering is properly derived from outside, that is from the surrounding connective tissue and does not form an integral part of such an organ or a structure.

perialgia, perialgy (s) (noun) (no po)
Excessive or intense pain: When Lynn had a very bad fall in winter on some ice on the sidewalk, she suffered from perialgia and could hardly cry for help.
Inflammation centered around a foreign body.
Around or close to the anus.
Inflammation of the tissue adjacent to the bile ducts.
A tumor surrounding a blood vessel.
1. Inflammation of the outer coat of or the tissues around a blood or lymph vessel.
2. Inflammation of the adventitia (outermost connective tissue covering) of a blood vessel or of the tissues surrounding it or a lymphatic vessel.
The outer envelope of a flower, consisting of either the calyx (sepals of one flower collectively) or the corolla (petals of a flower collectively), or both.
Around the aorta.
Inflammation of the outer coat of the aorta and of its surrounding structures.

Related "around, round, surrounding" units: ambi-; ampho-; circ-; circum-; cyclo-, -cycle; gyro-.