base pair

(bays payr)
Two nitrogen-containing bases (or nucleotides) that pair together to form the structure of DNA. The four bases in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T). These bases form specific pairs (A with T, and G with C). Base pair may also refer to the actual number of base pairs, such as 8 base pairs, in a sequence of nucleotides.