primitive
Definition
In general in computing a 'primitive' is the simplest type of programming language item. It may also refer to the smallest processing unit accessible by a programmer.
Source
Cryptographic primitive
KERI related
In KERI and ACDC it a serialization of a unitary value. A cryptographic primitive is the KERI-suite sense is the serialization of a value associated with a cryptographic operation including but not limited to a digest (hash), a salt, a seed, a private key, a public key, or a signature. All primitives in KERI MUST be expressed in CESR.