plural of water column

plural of clustered column

plural of flying column

plural of personal column

plural of society column

plural of social column

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

(anatomy) The vertebral column.

(mathematics) The vector space generated by all the column vectors of a matrix

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.