Table 1. Definition of terms utilized in this review, in order of appearance in the text.

Unless otherwise noted, terms are consensus working definitions proposed in the current work.

Term	Definition
Aging	The process resulting from accumulation of consequences of life, such as molecular and cellular damage, that leads to increased risk of functional decline, chronic diseases, and ultimately mortality
Healthspan	The period of life prior to onset of chronic disease and disabilities of aging, i.e., in good health (extended from28)
Biomarker of aging	A quantitative parameter of an organism that either alone or in a composite predicts biological age and ideally its changes in response to interventions
Biological age	Conceptually, an individual’s age defined by the level of age-dependent biological changes, such as molecular and cellular damage accumulation. In practical use, this is often summarized as a number matching the chronological age where the average person in a reference population shares the individual’s level of age-dependent biological changes
Chronological age	An individual’s age defined by time elapsed since birth
Age acceleration (age deviation)	The difference between biological age and chronological age (originally defined by29); we propose adoption of the term age deviation (AgeDev) for this concept to distinguish it from an increased rate of aging and encompass changes in both directions
Geroprotector	An agent or intervention that increases healthspan or lifespan and ameliorates [tested] biomarkers of aging (extended from8,30)