Biological process

The process whose specific outcome is the progression of the thymus over time, from its formation to the mature structure. The thymus is a symmetric bi-lobed organ involved primarily in the differentiation of immature to mature T cells, with unique vascular, nervous, epithelial, and lymphoid cell components.

Note that this term is reserved for annotation of gene products involved in the formation of the thymus itself, not for gene products involved in T cell differentiation in the thymus or elsewhere.