An antheridium is a haploid structure or organ producing and containing male gametes (called antherozoids or sperm). The plural form is antheridia, and a structure containing one or more antheridia is called an androecium.
What do you mean by Antheridium?
: the male reproductive organ of some cryptogamous plants.
Is Archegonia singular or plural?
Archegonium (plural = archegonia)