A prefix meaning part, partial or fragment, used in formation of compound words, e.g.
merocyanines are compounds related to cyanines but have a nitrogen atom at only one
end of the chromogenic system instead of at both ends.
Source:
PAC, 1995, 67, 1307
(Glossary of class names of organic compounds and reactivity intermediates based on
structure (IUPAC Recommendations 1995))
on page 1348