Specialized, fibrous connective tissue present in adults, forming the temporary skeleton in the embryo, providing a model in which the bones develop, and constituting a part of the organism’s growth mechanism.
Source: PAC, 2016, 88, 713. 'Glossary of terms used in developmental and reproductive toxicology (IUPAC Recommendations 2016)' on page 733 (https://doi.org/10.1515/pac-2015-1202)