Eccentricity or eccentric may refer to:

• Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal"

• Off-center, in geometry
• Eccentricity (graph theory) of a vertex in a graph
• Eccentricity (mathematics), a parameter associated with every conic section

• Orbital eccentricity, in astrodynamics, a measure of the non-circularity of an orbit
• Eccentric anomaly, the angle between the direction of periapsis and the current position of an object on its orbit
• Eccentricity vector, in celestial mechanics, a dimensionless vector with direction pointing from apoapsis to periapsis
• Eccentric, a type of deferent, a circle or sphere used in obsolete epicyclical systems to carry a planet around the Earth or Sun

• Eccentric (mechanism), a wheel that rotates on an axle that is displaced from the focus of the circle described by the wheel
• Horizontal eccentricity, in vision, degrees of visual angle from the center of the eye
• Eccentric contraction, the lengthening of muscle fibers
• Eccentric position of a surveying tripod, to be able to measure hidden points
• Eccentric training, the motion of an active muscle while it is lengthening under load
• Eccentricity, a deviation from concentricity

• Eccentric Club, a London gentlemen's club
• The Eccentric
• The Eccentrics

• All pages with titles beginning with eccentric
• All pages with titles containing eccentric*
• Acentric (disambiguation)