tetrapyrrole
noun
tet·ra·pyr·role ˌte-trə-ˈpir-ˌōl 
: a chemical group consisting of four pyrrole rings joined either in a straight chain or in a ring (as in chlorophyll)
Example Sentences
Recent Examples on the Web Chlorophyll is actually a generic name for a member of the tetrapyrrole family of organic compounds. 
Kevin Dayhoff, baltimoresun.com/maryland/carroll, 2 Oct. 2020
Kevin Dayhoff, baltimoresun.com/maryland/carroll, 2 Oct. 2020 Word History
First Known Use
circa 1928, in the meaning defined above
Medical Definition
tetrapyrrole
noun
tet·ra·pyr·role
variants also tetrapyrrol
ˌte-trə-ˈpi(ə)r-ˌōl
: a chemical group consisting of four pyrrole rings joined either in a straight chain (as in phycobilins) or in a ring (as in chlorophyll)