C-DNA, also known as complementary DNA, refers to a double-stranded DNA molecule that is synthesized using a single-stranded RNA molecule as a template. This process is essential for researchers and scientists to study and understand the expression levels of specific genes in organisms. However, there are several synonyms for c-DNA, such as reverse-transcriptase cDNA, blunt end cDNA, oligo-capped cDNA, and tagged cDNA. Each of these synonyms has its unique advantages and disadvantages, and scientists use them according to their experiment requirements. Nevertheless, these synonyms allude to the same concept of complementary DNA synthesis and play a vital role in modern-day genomic research.