glans

Glans in Latin means acorn. It also meant anything acorn-shaped — an acorn-shaped bullet for a sling, or certain anatomical structures that resemble acorns. The word was applied to the small, rounded body structures that produce and secrete substances. Lymph nodes, tonsils, and other rounded tissue masses looked like acorns to the anatomists who named them.

Galen described numerous glandular structures, though he did not understand their function. He believed glands existed to support blood vessels, acting as cushions where vessels branched. The idea that glands produce specific substances — hormones, enzymes, sweat, saliva — was not established until the seventeenth and eighteenth centuries. The word preceded the understanding by nearly two millennia.

The endocrine glands — thyroid, pituitary, adrenal, pancreas — produce hormones that regulate the entire body. The exocrine glands — salivary, sweat, sebaceous — produce substances that are secreted onto surfaces. The distinction between endocrine (secreting into blood) and exocrine (secreting onto surfaces) was established in the nineteenth century. The word 'gland' covers both, because both were named for shape, not function.

The word entered everyday English through a mildly embarrassing route. 'Swollen glands' — actually swollen lymph nodes — is the most common non-medical use. The phrase is technically wrong (lymph nodes are not glands in the modern sense), but it persists because 'swollen lymph nodes' sounds clinical and 'swollen glands' sounds like something your mother says.