Segmentation

noun

1. Division into segments.
3. The act of cutting into segments; a division into segments; the condition of being divided into segments; the manner in which a segmented part is divided.
4. The act or process of dividing into segments; specifically (Biol.), a self-division into segments as a result of growth; cell cleavage; cell multiplication; endogenous cell formation.
5. the cavity formed by the arrangement of the cells in segmentation or cleavage of the ovum; the cavity of the blastosphere. In the gastrula stage, the segmentation cavity in which the mesoblast is formed lies between the entoblast and ectoblast. See Illust. of Invagination.