The term 'birth to death' is often used to refer to the LIFE of a person, from the moment they are born until the moment they die. This can be further broken down into two terms: 'LIFE' and 'lifespan'. LIFE is defined as the period of time between birth and death, while lifespan is defined as the average length of time that a person or species lives. Both terms are used to describe the duration of a person's LIFE, from beginning to end.