Biological immortality refers to the ability of an organism to live indefinitely without experiencing the effects of aging or disease. There are several synonyms for this term, including cellular immortality, chronic youthfulness, and perpetual vitality. Another term that is often used in relation to biological immortality is regeneration, which refers to the ability of certain organisms to regrow damaged or lost tissues. Some scientists also use the term negligible senescence to refer to organisms that do not experience significant declines in physical function over time. While these terms may have slightly different nuances and connotations, they are all related to the idea of maintaining long-term health and vitality.