Final answer:
Splicing is not a recognized stage of protein synthesis in both prokaryotes and eukaryotes; it's a process specific to eukaryotic mRNA maturation.
Step-by-step explanation:
The stage of protein synthesis that is not recognized in both prokaryotes and eukaryotes is splicing. Protein synthesis, or translation, in both prokaryotes and eukaryotes consists of three primary stages: initiation, elongation, and termination. Splicing is a process that occurs in the maturation of mRNA in eukaryotes after transcription and before translation, where introns are removed and exons are joined together. This does not occur in prokaryotes, as their mRNA does not contain introns and is generally used immediately for protein synthesis without modification.