Algae isn't a single species, but a diverse group of organisms. So, it doesn't have one single technical name.

However, the scientific term for the study of algae is Phycology.

Here are some other ways to refer to algae:

* Phytoplankton: This term refers to algae that live in the water column, which includes many types of microscopic algae.

* Seaweed: This term is often used to describe larger, multicellular algae that grow in marine environments.

* Macroalgae: This is a more general term for large algae, regardless of their habitat.

* Microalgae: This term refers to small, single-celled algae.

Ultimately, the best term to use depends on the context and the specific type of algae you're referring to.