The distinction between special effects and visual effect was there in the 20th century.
In general:
Scenic backdrops/set backings/cycloramas/translights are on-set artwork/photographs used to extend a setting. They are not considered a special effect.
"Special effect" means an on-set effect, like squibs, fire, smoke coming off Chekov's arm, etc.
Matte paintings/matte shots/traveling mattes all refer to post production processes that involved the generation of mattes
Optical effects typically meant an optical printer was used.
CGI is a catch-all for effects created on or altered using computers.
In general:
Scenic backdrops/set backings/cycloramas/translights are on-set artwork/photographs used to extend a setting. They are not considered a special effect.
"Special effect" means an on-set effect, like squibs, fire, smoke coming off Chekov's arm, etc.
Matte paintings/matte shots/traveling mattes all refer to post production processes that involved the generation of mattes
Optical effects typically meant an optical printer was used.
CGI is a catch-all for effects created on or altered using computers.