septanucleotide🔊nounEtymology From septa- + nucleotide.1Biology, Genetics, Medicine, Natural sciences, Sciences A codon containing seven nucleotides.Further, the septanucleotides were not labeled by α-³²ᵖ-CTP while the unique 5' terminal oligonucleotide was not labeled by α-³²ᵖ-UTP.1973, Sewell P. Champe, Phage, page 389: