Dense, collagenous fibrous coat surrounding an anatomical structure, and in particular surrounding the ovaries, testicles, and corpora cavernosa of the penis.
Source:
PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 816 (https://doi.org/10.1515/pac-2015-1202)