Indehiscent fruit do not open at maturity in a pre-defined way, but rely on predation or decomposition to release the seeds.
Some, but not all, indehiscent fruits are included in specialized morphological categories such as achene, berry, caryopsis, cypsela, drupe, hesperidium, loment, pepo, pome, samara, syconium.
See also: List of plants with dehiscent fruits