A soft gelatin capsule that holds a liquid or oil-based fill.
A softgel is a one-piece sealed capsule with a soft, flexible gelatin (or plant-based) shell that encloses a liquid or oil. It's the standard form for fat-soluble and oil-based supplements — fish oil, vitamin D3, vitamin E, CoQ10 — because those dissolve in oil rather than pressing into a dry powder.
Compared with a dry capsule or tablet, a softgel is better suited to oils and can be easier to swallow, but it usually can't hold as large a powder dose.