Aza
Full definition of aza
Noun
aza
(uncountable)- (chemistry, attributive) A nitrogen atom substituted for a carbon atom within a ring.
- 2003, Heinrich Zollinger, Color Chemistry http://books.google.com/books?id=0Ynge4E5rqYC, , page 73:"However, aza N-atoms (~N=) have to be counted, if they replace methine groups in the chain."