A natural killer cell that is developmentally immature and expresses natural killer cell receptors (NKR). [ GOC:add http://www.ncbi.nlm.nih.gov/pubmed/12457618 http://purl.obolibrary.org/obo/go/references/0000031 https://www.worldcat.org/search?q=bn%3A0781735149 ]
Synonyms: immature NK cell