(
_paradoxboy_ made me puppet out.)
Via
Grandpa Wikipedia:
The official commentary included in the CD set Celebrate: The Three Dog Night Story, 1965-1975 states that vocalist Danny Hutton's then-girlfriend June Fairchild suggested the name after reading a magazine article about indigenous Australians, in which it was explained that on cold nights they would customarily sleep in a hole in the ground whilst embracing a dingo, a native species of wild dog. On colder nights they would sleep with two dogs and if a night was especially cold, it was a "three dog night"
Forlorn.
Ponderous.
Manic.