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Any of a group of small proteins, originally isolated from the thymus, that are involved in a variety of functions including angiogenesis, cell migration, regulation of actin polymerization, and the immune response.
(Biology) a hormone secreted by the thymus which stimulates the immune system
thy•mo•sin(ˈθaɪ mə sɪn)
a hormone, produced by the thymus gland, that promotes the development of T cells from stem cells.