glo·mer·u·lus 
(glō-mĕryə-ləs)
(glō-mĕryə-ləs)n. pl. glo·mer·u·li (-lī′)
1. A small cluster or mass of blood vessels or nerve fibers.
2. A tuft of capillaries situated within a Bowman's capsule at the end of a renal tubule in the vertebrate kidney that filters waste products from the blood and thus initiates urine formation.
[New Latin, diminutive of Latin glomus, glomer-, ball.]