(MAR-jih-nul zone lim-FOH-muh) 
An indolent (slow-growing) type of B-cell non-Hodgkin lymphoma that begins forming in certain areas (the marginal zones) of lymph tissue. There are three types based on whether it forms in the spleen, lymph nodes, or other lymphoid tissue that contains a lot of B cells (a type of white blood cell). Also called marginal zone B-cell lymphoma and MZL.