Apophysis - a widening of the rhizoid just beneath a sporangium; a subsporangial swelling of the rhizoidal axis.
Basal Body - the base of a flagellum consisting of a cylinder of nine triplet microtubules. This structure arises from the centriole and is also called the kinetosome.
Catenulate - A term used to describe chains of intercalary swellings found in the rhizoids of members of the Nowakowskiella clade.
Endobiotic - reproductive structure is inside of the substrate or host cell.
Endogenous - a form of thallus development in which the nucleus remains in an encysted zoospore that simply enlarges to form one or more sporangia.
Epibiotic - reproductive structure is on the outside of the substrate or host cell.
Eucarpic - only a part of the thallus is converted into a reproductive body.
Exogenous - Refers to manner in which encysted zoospores germinate. Cyst germinates to produce a tube through which the protoplast moves. New thallus develops outside of cyst.
Flagellum - a hairlike structure with internal microtubules surrounded by a continuation of the plasma membrane that serves to propel a motile cell such as a zoospore.
Holocarpic - refers to an organism with a thallus that is converted entirely into one or more reproductive structures.
Kinetosome - see basal body.
Monocentric - a thallus that produces a single reproductive organ (sporangium or resting spore).
Operculum - a hinged cap on a sporangium.

Note: The operculum can also completely detach from the sporangium and float away, so not all opercula remain hinged. This is the main reason why you have to watch zoospore discharge so you can see if an operculum is present or not.

Polycentric - a thallus with many centers at which reproductive organs (sporangia or resting spores) are formed.
Rhizomycelium - a enucleate rhizoidial system extensive enough to resemble the indeterminate mycelium produced by Ascomycetes, Basidiomycetes, and Zygomycetes; one of several thallus arrangements in the order Chytridiales.
Rumposome - A complex structure composed of interconnecting tubules that lies at the posterior end of the zoospore of Monoblepharella and some other chytrids.
Zoospore - a motile, asexually produced spore.