Eccentric (mechanism), a wheel that rotates on an axle that is displaced from the focus of the circle described by the wheel
Eccentric position of a surveying tripod to be able to measure hidden points
Orbital eccentricity, in astrodynamics, calculated from orbital state vectors as an absolute value of eccentricity vector or using other methods based on orbital energy and angular momentum.
Eccentric anomaly, the angle between the direction of periapsis and the current position of an object on its orbit.
Eccentric (astronomy), a type of deferent, a circle or sphere used in obsolete astronomical systems to carry a planet around the Earth or Sun.