: Brands like Dewar's use a "Double Double" aging process involving multiple stages of blending and resting in different casks, such as sherry casks, to enhance complexity. Similarly, Aberlour 18 Year Old is a well-known "double cask matured" Scotch.
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
: Research into plant reproduction sometimes identifies "double mature embryo sacs" in ovules, which can complicate genetic interpretations. Agriculture Intracranial double teratomas - ScienceDirect.com : Brands like Dewar's use a "Double Double"