the GNU version of the Collaborative International Dictionary of English
noun-plural. The long, branching filaments of which the mycelium (and the greater part of the plant) of a fungus is formed. They are also found enveloping the gonidia of lichens, making up a large part of their structure.
Word Usage
""When spores reach a favorable place to grow, they germinate and send out long, thin filaments called hyphae," she said."