-di·al
\-ˈdīˌal\  noun suffix 
(-s) 
Etymology: International Scientific Vocabulary, from di- + -al 
 : containing two aldehyde groups replacing two methyl groups at the ends of an aliphatic hydrocarbon chain 
< heptanedial OCH(CH2)5CHO >
< heptanedial OCH(CH2)5CHO >