Of the three termination codons UAG was the first termination codon to be discovered. It was named amber after a graduate student in Germany named Bernstein (means amber in German). This graduate student helped in the discovery of the class of mutations. The other two termination codons were obviously given the name of the colors only to maintain uniformity.
Termination codons found in mRNA will not specify any amino acid and as such stop the process of translation and bring about the release of the peptide chain from ribosomes. No tRNA molecules have anticodons complementary to the termination codons found in mRNA. Termination codons seem to have some affinity to proteins called release factors which bring about the release of the protein chain. In prokaryotes there are three release factors RF-1, RF-2 and RF-3. RF-1 recognizes the amber and ochre codons while RF-2 recognizes ochre and opal codons, RF-3 stimulates RF-1 and RF-2 ultimately releasing the newly synthesized peptide chain. In eukaryotes there is a single factor (RF protein) which is capable of recognizing all the three termination codons.