oma: Suffix meaning a swelling or tumor. Many words in medicine end in -oma. Some examples include adenoma, atheroma, carcinoma, condyloma, fibroma, glaucoma, glioma, granuloma, hemangioma, hematoma, lipoma, lymphoma, melanoma, meningioma, myeloma, neuroblastoma, neuroma, papilloma, retinoblastoma, sarcoma, and xanthoma.
The medical suffix -oma came from the Greek suffix -oma which was used in a different way -- to transform a verb into a noun.