The use of three bases to code for an amino acid is called the

I think it is called translation. It is the second major step in gene expression, the mRNA is read according to the genetic code, which relates the DNA sequences to the amino acid sequence in proteins. Each group of three bases in mRNA constitutes a codon, and each codon specifies a particular amino acid. The process takes place in the cytoplasm, where ribosomes or the ER synthesize proteins after the process of transcription.