A centrocyte generally refers to a B cell with a cleaved nucleus, as may appear in e.g. follicular lymphoma.
During B cell development, centrocytes are formed following the cessation of centroblast proliferation. Centrocytes test their newly mutated anti-binding sites (CDR loops) by re-expressing antigen on their surface.
Centrocyte can also refer to a cell with a protoplasm that contains single and double granules of varying size stainable with hematoxylin, as seen in lesions of lichen planus, or a nondividing, activated B cell that expresses membrane immunoglobulin.