n The state of surpassing or going beyond limits; the being of a measure beyond sufficiency, necessity, or duty; that which exceeds what is usual or proper; immoderateness; superfluity; superabundance; extravagance; as, an excess of provisions or of light.
n The degree or amount by which one thing or number exceeds another; remainder; as, the difference between two numbers is the excess of one over the other.
n An undue indulgence of the appetite; transgression of proper moderation in natural gratifications; intemperance; dissipation.
n (geometry) spherical | Spherical excess, the amount by which the sum of the three angles of a spherical triangle exceeds two right angles. The spherical excess is proportional to the area of the triangle.
n (British|insurance) A condition on an insurance policy by which the insured pays for the first part of any claim, in exchange for a lower premium.