Thymi, also known as thymuses, are small glandular structures in the human body that are involved in the development and maturation of T-cells, which play a key role in immune system function. Synonyms for thymi include thymus gland, which is the more formal medical term, and simply thymus, which is the shortened informal version. Other synonyms for thymi include thymus organ, thymic gland, and lymphoid organ. While these terms all refer to the same type of gland, they may be preferred in different contexts depending on the audience and the level of formality required.