As nouns the difference between gazebo and pavillion
is that gazebo is a belvedere, either a type of summer-house or a roofed, detached porch-like structure, usually in a yard, park or lawn while pavillion is .
gazebo
Noun
(en-noun)
A belvedere, either a type of summer-house or a roofed, detached porch-like structure, usually in a yard, park or lawn.
pavillion
English
Usage notes
The Oxford English Dictionary marks this spelling as "now nonstandard" .