In the field of cryptography, a Scrypt pertains to an alternative proof-of-work (PoW) algorithm to the usual SHA-256 that is used for Bitcoin mining. What it is basically is a password-based key derivation function created by Colin Percival. The original intention behind its creation is for the usage of the Tarsnap online backup service; it was purposefully designed in such a way that it makes it costly for fraudulent entities to administer large-scale custom hardware attacks through the requirement of large amounts of memory.
Back in 2016, the Scrypt algorithm was published by the IETF as RFC 7914. There is a simplified version of Scrypt that is used as a PoW scheme by a number of digital coins. This was first put into use by an anonymous programmer who was only known as ArtForz in Tenebrix. Fairbrix and Litecoin followed this pattern soon after.