Pretty recently I had to try to find a definition of "oval" as a part of a dispute over the limits of a patent that used the term. It turns out "oval' is basically whatever the hell you want it to be as long as it vaguely resembles an elongated circle. Ellipse, egg, "skating rink", two different sized arcs connected by straight lines, and a bunch of other oddball shapes are all called ovals depending on the source you look at. Math textbooks, other patents, dictionaries, etc. could not agree over what the word actually means. I immediately recognized that exact screenshot you posted from the research!