Freely redistributable software (FRS) is software that anyone is free to redistribute but not to modify (free software is not usually categorised as FRS). The more ambiguous term, freeware (as well as shareware), is often used to refer to FRS.
FRS generally comes in the form of executable binaries and is often used by proprietary software companies and authors to showcase their work or to encourage the user to buy full products from them (in the case of shareware, demo or trial versions).