Zoology: what is the difference between a perentie and a goanna?

Goanna

Goanna head2.jpg
Lace Monitor (Varanus varius)

Scientific classification

Kingdom: Animalia
Order: Squamata
Suborder: Scleroglossa
Family: Varanidae
Genus: Varanus in part
Species : A goanna is any of several Australian monitor lizards of the genus Varanus, as well as certain species from Southeast Asia.
Around 30 species of goanna are known, 25 of which are found in Australia.
https://en.wikipedia.org/wiki/Goanna

The perentie (or perente) (Varanus giganteus) is the largest monitor lizard or goanna native to Australia, and the fourth-largest living lizard on earth, after the Komodo dragon, Asian water monitor, and the crocodile monitor.
https://en.wikipedia.org/wiki/Perentie