In biology terms the difference between alga and archaeplastid
is that alga is any of many aquatic photosynthetic organisms, whose size ranges from a single cell to giant kelps and whose form is very diverse; some are eukaryotic and some prokaryotic; includes the seaweeds while archaeplastid is any plant or alga of the taxon Archaeplastida
alga
Noun
(algae)
(biology) Any of many aquatic photosynthetic organisms, whose size ranges from a single cell to giant kelps and whose form is very diverse; some are eukaryotic and some prokaryotic; includes the seaweeds.
Usage notes
* (term) is a non-standard plural.
Hyponyms
* seaweed