intensity
n. C / Un. the quality of being very strong or powerful. You use it to describe how much energy something has, like a bright light or a deep feeling.
n. the measurable amount of a property, such as force, brightness, or a magnetic field. Often used to describe the degree of emotional or physical energy present in a situation.
The intensity of the sun is strongest at noon.
Geologists measure the intensity of an earthquake to understand how much damage it might cause to local buildings.
As the star approached the end of its life cycle, the intensity of its radiation increased significantly, affecting the atmosphere of nearby planets.
From intense + -ity. Cf. also Medieval Latin intensitas.
Uncountable when referring to the general quality of being intense; countable when referring to specific measurable levels or instances.