axillo-, axill-, axil-

(Latin: armpit; angle; borrowed directly from Latin ala which meant both "wing" and "the hollow under a wing or an arm")

armpit (s) (noun), armpits (pl)
The pyramidal hollow between the upper arm and the chest, confined in front by the pectoral or breast muscles, behind by the shoulder blade and its muscles, and running up to a point beneath the collarbone: The armpit consists of the axillary vessels and nerves that run to the arm, also much fatty tissue, many sweat glands and lymphatic glands which act to remove bacteria and certain proteins from the tissues, transport fat from the small intestine, and supply mature lymphocytes to the blood.

The lymphatic glands in the armpits are important, because in poisoned wounds of an arm, they may become inflamed, resulting in abscess (inflamed tissue and pus); and still more, because in cancer of the breast, they may become infected with cancer, and have to be removed with the breast.

Wounds in an armpit are dangerous for the outer, front, and back walls, because large blood vessels are located there.

—The information contained in the definition and
explanatory sentences were compiled from
Black's Medical Dictionary, 35th edition, Edited by C.W.H. Havard;
Barnes & Noble Books; Totowa, New Jersey, USA; 1987; page 53.
axil (s) (noun), axils (pl)
In plants, an upper angle or point of separation between the upper side of a branch, leaf, flower, or stalk of a leaf, and the stem or branch from which it grows: The axils of seed plants usually contain one or more axillary, or lateral, buds, from which a leaf shoot or a flower, thorn, or tendril may develop.

An axil is known as the angle that is formed by a leaf or branch with the stem.

axilla (s) (noun), axillae (pl)
The armpit, or the cavity beneath the junction of the arm and shoulder: Luther had a strong odor coming from his axillae which indicated that he needed to take a shower and to use some deodorant to keep the strong smell under his arms from bothering other people.
axillant (adjective), more axillant, most axillant
A reference to that which is forming or growing in an armpit: For some unknown reason, Shelly was feeling an axillant pain in her left armpit.
axillar (s) (noun); axillars, axillaries (pl)
The armpits: The axillars consist of lymph nodes, arteries, nerves and other bodily structures.
axillary (adjective) (not comparable)
Pertaining the pyramid-shaped space forming the underside of the shoulder between the upper arm and the side of the chest: Jesse was being examined by Dr. Clegg to determine if there was an infection in the axillary nerves, or in the blood and lymphatic vessels of his armpit.

The axillary section of the subclavian (under the collarbone) artery that distributes blood to the axilla, chest, shoulder, and upper extremities.

axillary bubo (s) (noun), axillary buboes (pl)
An inflamed swelling of lymph nodes in the areas of the armpits, neck, and other bodily parts: Dr. Roberts told Tony's cousin that his axillary bubo, or painfully enlarged lymph nodes, was probably a result of bubonic plague that is usually transmitted by the bite of fleas, probably from an infected rat, during his travels in Africa.
axillary cavity (s) (noun), axillary cavities (pl)
The hollow spaces under the arms of people where they are joined to the shoulder: When Tim was studying basic anatomy in his high school, he learned that axillary cavities are medical terms for the armpits.

axillary dissection, axillary node dissection (s) (noun); axillary dissections, axillary node dissections (pl)
The surgical removal of lymph nodes in the armpits: Axillary dissections are performed through an incision in the axilla or as part of a modified radical mastectomy for women with invasive breast cancer.
axillary fascia, fascia axillaris (s) (noun) (only singular)
The flat band of tissue below the skin that covers tissues, separates different layers of tissue, and encloses muscles: Axillary fascia forms the basic area of the axilla or the underarm area.
axillary fossa (s) (noun), axillary fossae (pl)
The small hollows under the arms where they join the body at the shoulder: Jill and Kay were up to their axillary fossae, or almost up to their stretched out arms, in water."
axillary gland (s) (noun), axillary glands (pl)
Any of numerous nodes (collections of tissue) situated in the areas of underarm veins that receive lymphatic drainage (almost colorless fluid that travels through vessels and carries cells that help fight infection and disease) from the upper limb, pectoral girdle (bones supporting the front or upper parts of the body), and mammary gland (two half-moon-shaped glands on either side of the adult female chest, which make up the breast): Jenny's primary physician, Dr. Smith, tried to explain how the axillary glands function and how this might explain why she was having an abnormal feeling in her armpits.
axillary nerve (s) (noun), axillary nerves (pl)
The nerves in the armpits: Some of the fibers of the axillary nerves supply the capsules that surround the shoulder joints with connective tissue.

When Sally's little brother tickled her axillary nerves, she couldn't keep herself from laughing and, after a while, it started to be painful to laugh so much!

axillary region (s) (noun), axillary regions (pl)
The area of the upper chest surrounding the armpits which are lateral (to the side) of the pectoral (breast or chest) region: Viola had her axillary regions checked by Dr. Jones to see if there was any indication of cancer in that part of her body.
axillary temperature (s) (noun), axillary temperatures (pl)
The body heat as recorded by a thermometer placed in the armpit: Kelvin had his axillary temperature measured by his doctor and the reading was normal in that it was .75 degrees Fahrenheit which was less than his oral (mouth) temperature.