primary root

noun Botany.

the first root produced by a germinating seed, developing from the radicle of the embryo.

Origin of primary root

First recorded in 1885–90

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

primary root in Science

The first root of a plant, originating in the embryo. In gymnosperms, eudicotyledons, and magnoliids, the primary root develops into the taproot. In monocotyledons, the primary root disintegrates as the lateral roots develop into a system of fibrous roots.