The term accelerator comes from the startup scene and means exactly what it says. Accelerators are support programs for startups that already have a well-thought-out business model. The aim is to accelerate the development and growth of the startup—for example, by providing access to networks, capital, or coaching from mentors. Accelerator programs usually last between a few weeks and several months.
Source: Impact Hub Tirol, 2021
https://www.tirol.impacthub.net/glossar