Real Dictionary

spleen in American English
a large, vascular, lymphatic organ in the upper left part of the abdominal cavity of vertebrates, near the stomach: it has various functions in modifying the structure of the blood, and was formerly regarded as the seat of certain emotions
noun: a highly vascular, glandular, ductless organ, situated in humans at the cardiac end of the stomach, serving chiefly in the formation of mature lymphocytes, in the destruction of worn-out red blood cells, and as a reservoir for blood

spleen in British English
noun: a spongy, highly vascular organ situated near the stomach in humans. It forms lymphocytes, produces antibodies, aids in destroying worn-out red blood cells, and filters bacteria and foreign particles from the blood