: Research into plant reproduction sometimes identifies "double mature embryo sacs" in ovules, which can complicate genetic interpretations. Agriculture Intracranial double teratomas - ScienceDirect.com
The phrase appears in various academic papers to describe dual occurrences or specific biological states: double mature
In the spirits industry, "double mature" refers to aging a liquid in one type of cask and then transferring it to a different cask type to add a second layer of flavor. double mature