The nRF Connect SDK provides a set of example applications that show how to implement typical user scenarios using Nordic Semiconductor devices. Applications typically include a fully integrated software stack and can serve as a starting point for developing your product. They use interface drivers and libraries from the nRF Connect SDK and its set of repositories to implement a specific use case, while Samples showcase a single feature or library.
Some applications target custom hardware designed for a specific use case. You can also run them on different hardware like a generic development kit, but with limited functionality.