Glomerulus, the spherical capillary tuft within the kidney, is the diminutive form of the Latin word for glomus, something wound into a ball, usually used in reference to yarn. These "little balls of yarn", of which there are about a million in a kidney with each serving a nephron, were discovered in 1666 by the preeminent Italian anatomist, Marcello Malpighi.

Malpighi also was the first to describe capillaries. His accurate observations of microscopic structure were amazing accomplishments given the primitive state of microscopy at the time.

Glomeruli were known as Malpighian bodies until 1788, when the term glomerulus was introduced by the Russian anatomist Alexander Schumlansky.

Non-anatomical words coming from glomus include conglomerate and agglomerate.

Marcello Malpighi (1628-1694) complete-body.net