%columnar%

a. [ L. columnaris, fr. columna. ] Formed in columns; having the form of a column or columns; like the shaft of a column. [ 1913 Webster ]

Columnar epithelium (Anat.), epithelium in which the cells are prismatic in form, and set upright on the surface they cover. --
Columnar structure (Geol.), a structure consisting of more or less regular columns, usually six-sided, but sometimes with eight or more sides. The columns are often fractured transversely, with a cup joint, showing a concave surface above. This structure is characteristic of certain igneous rocks, as basalt, and is due to contraction in cooling. [ 1913 Webster ]