mero

https://doi.org/10.1351/goldbook.M03836
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.
M03836.png
Source:
PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1348 [Terms] [Paper]