Health

From the helpfile:

Health/Hit points:

Health, or hit points, is the amount of damage you can take before falling
unconscious. Although you will not die immediately after falling unconscious,
you will be much easier to hit. Maximum hit points also reflect the amount of
health you can go below 0 without dying. The exact percent is said to be 
known by a few sages, scattered throughout the land. Hit point regeneration is
determined by your constitution. To see more information regarding constitution
see, 'help constitution.'

Score Sheet Topic

Score Sheet Topic: Health (hit points)

This field represents the current and maximum health you have. Health is one of
the most important and noted statistics you have. When your health drops to 
zero you will fall unconscious and will be much more susceptible to damage.

For more information, see: help health