ˈdīəˌzēn, dīˈaz-, -zə̇n noun
( -s )
Etymology: International Scientific Vocabulary di- + az- + -ine
1. : any of three parent compounds C 4 H 4 N 2 containing a ring composed of four carbon atoms and two nitrogen atoms and distinguished by indication of the positions of the nitrogen atoms or by trivial names:
a. : pyridazine
b. : pyrimidine
c. : pyrazine
2. : any of a large class of derivatives of the three parent diazines