Mortality is the fact that all living things eventually die. It's one of the fundamental realities of life: humans, animals, plants, everything that lives will someday stop living.

When doctors study mortality rates, they're looking at how many people die in a particular group or time period. A country with high infant mortality has many babies who don't survive their first year. Scientists who study mortality try to understand what causes death and how to help people live longer, healthier lives.

The word often appears when people think seriously about life's limitations. A character in a story might contemplate their own mortality after a close call, suddenly aware that their time is limited. This awareness can make life feel more precious. When you realize that your years are finite, each birthday, each friendship, each accomplishment can feel more meaningful.

The opposite of mortal is immortal, meaning unable to die. Gods in ancient myths were immortal, but humans are mortal beings.