Non-Volatile Storage (NVS) is a broad collection of technologies and devices that do not require a continuous power supply to retain data or program code persistently on a short- or long-term basis.
Three common examples of NVS devices that persistently store data are tape, a Hard Disk Drive (HDD) and a Solid-State Drive (SSD). The term non-volatile storage also applies to the semiconductor chips that store the data or controller program code within devices such as SSDs, HDDs, tape drives and memory modules.
Source: https://searchstorage.techtarget.com/definition/nonvolatile-storage