2.35:1
Refers to the aspect ratio of a given post where the width of the image / frame is 2.35 times its height. This aspect ratio is referred to in the film world as "CinemaScope". It was a process for creating a wide image on 35mm film by using an anamorphic lens to vertically compress the wide frame onto the film strip, and when the film was projected in theaters, another anamorphic lens would be in a horizontal position, to bring back the natural look.
Keep in mind that CinemaScope (2.35:1) isn't 21:9 (2.333:1). For posts that use that ratio, go to 21:9.
This ratio simplifies down to 47:20. You can also just use ratio:2.35 to find things with APPROXIMATELY this ratio.