Definitions of important terms, based on Butler (1954), Hawksworth (1981), Jeffries and Young (1994), Alexopoulos (1996), Lawrey and Diederich (2003), Gams et al. (2004), Piepenbring (2015), Haelewaters et al. (2018a), Sun et al. (2019), Moore et al. (2020), Bermúdez-Cova et al. (2022), and Diederich et al. (2022). Definitions colored in green represent fungicolous fungi that cause little or have no effect on the fungal hosts, while definitions colored in orange represent fungi that have negative effects on the hosts.