A small, independent, military land unit capable of rapid mobility, often using guerrilla tactics against a larger force.

(anatomy) The vertebral column.

A group of people which clandestinely undermines a larger group, such as a nation, to which it is expected to be loyal. / Used other than figuratively or idiomatically: see fifth, column.

(anatomy) The series of vertebrae that protect the spinal cord; the spinal column.

plural of vertebral column

The total amount per unit area of a material suspended in a fluid or in a cloud in space, measured along the length of a column.

(physics, chemistry) An apparatus for the separation of the volatile components of a liquid by means of fractional distillation, sometimes accompanied by selective adsorption

plural of column space

plural of Morris column

(automotive) a column originating in the dashboard and ending at the steering wheel / (aviation) a column ending in the flight yoke, whose manipulation allows for the control of pitch