follicle 2 topics · 2 sources Healthcare› MedicineCancer(FOL-i-kul) A sac or pouch-like cavity.National Cancer Institute — Dictionary of Cancer Terms Cite Science› Biotechnology and GeneticsFood BiotechnologyAn enclosing cluster of cells that protects and nourishes a cell or structure within. Thus a follicle in the ovary contains a developing egg cell, while a hair follicle envelops the root of hair.UN Food and Agriculture Organization — Glossary of Biotechnology for Food and Agriculture Cite