Which term refers to the ability of two things to hold firmly together when they do not adhere?

The correct term that refers to the ability of two things to hold firmly together without adhering is retention. Retention is a crucial concept in dentistry as it pertains to how well materials bond or stay connected in a given environment, particularly in scenarios where traditional adhesion might not be effective.

In dental applications, retention can be particularly relevant when discussing restorations such as crowns, bridges, or during procedures involving the placement of certain dental materials that rely on mechanical means for stability rather than chemical bonding. Understanding retention helps dental professionals choose appropriate materials and techniques for ensuring that dental restorations remain intact and functional over time.

The other terms do not align with this concept; they refer to different mechanisms or processes within dentistry. Flow relates to the ability of a material to move and adapt to a shape, adhesion pertains specifically to the attraction between different substances at a molecular level, and curing typically refers to the hardening process of materials like dental resins, often through chemical activation or light exposure.