Cyanobacteria and Eubacteria

Cyanobacteria noun - Predominantly photosynthetic prokaryotic organisms containing a blue pigment in addition to chlorophyll; occur singly or in colonies in diverse habitats; important as phytoplankton.

Eubacteria and cyanobacteria are semantically related. In some cases you can use "Eubacteria" instead a noun "Cyanobacteria".

Eubacteria noun - A large group of bacteria having rigid cell walls; motile types have flagella.

Cyanobacteria and eubacteria are semantically related. Sometimes you can replace term "Cyanobacteria" with "Eubacteria", this nouns are similar.