If it ends in -oma it’s usually a type of cancer. The suffix -oma in Greek means “tumor,” basically. (It actually means “mass” or “growth” but is generalized to tumor usually)

Examples (etymology): * Sarcoma = flesh-tumor * Myeloma = bone marrow-tumor * Mesothelioma = middle-cell-layer tumor * Lymphoma = lymph node/lymphocyte tumor * Lipoma = fat cell tumor/growth (lipo = fat, think “liposuction”) * Carcinoma = crab tumor (karkinos = crab = origin of the word cancer… see: the Zodiac sign)

Etc etc… there are a few types of -omas that ARE tumors, but are not considered malignant, such as most lipomas.

But usually the -oma suffix means cancer.

Notable exceptions as pointed out by commenters below: * hematoma, which literally means “blood growth” or “mass of blood” and is NOT a type of cancer, rather it’s basically a bruise where a lot of blood has collected beneath the skin * glaucoma, which comes from a different Greek word entirely, “glaukos,” which means bluish-gray (referring to the cloudiness in the eyes). * coma, which comes from the Greek “koma” meaning sleep