Is there a name for cropping illustrations into ovals like this?

Question

There is a certain type of illustration, that I typically associate with old storybook illustrations, where the illustration has been cropped into an oval shape. I've attached some examples here one from some old childrens book that I don't know the name of, and the other from Alice in Wonderland.

I'm wondering if there is a specific name for this practice/type of image since I would like to find more examples and information about it (i.e. was there a technical reason why it was done, is it simply a style choice etc.). For this question I'm primarily interested in the name of the practice if there is one.

Answer 1

Oval Vignette

A vignette, in graphic design, is a unique form for a frame to an image, either illustration or photograph. Rather than the image's edges being rectilinear, it is overlaid with decorative artwork featuring a unique outline. This is similar to the use of the word in photography, where the edges of an image that has been vignetted are non-linear or sometimes softened with a mask – often a darkroom process of introducing a screen. An oval vignette is probably the most common example.

Source Wikipedia

...Hamilton’s 1793 edition included an essay on The Seasons, ... The title page of the edition proclaims its ambitious rationale, with an oval vignette showing the four seasons as rococo putti. ...

From Visual Interpretations, Print, and Illustrations of Thomson’s The Seasons, 1730 – 1797

Answer 2

It's elliptical frame (or vignette, if its inside bigger rectangular frame)

Ellipse is one of those regular forms which has been hundreds, maybe thousands of years possible to produce mechanically as precisely as circles, triangles and rectangles.

Ellipsograph which is called "Trammel of Archimedes" (see NOTE1) can be made sturdy enough for cutting tools, so elliptical plates, salvers, frames, mirrors etc. everyday things are crafted by artisans as easily as circular ones.

It's no wonder that also artists and graphic designers have taken elliptical frames into use, the form is a part of our common visual vocabulary.

Term "oval" ie. egg-like in Latin means a larger set of non-circular convex closed curves in analytical plane geometry. Ellipse is a special case. In everyday talk saying "oval" and meaning "ellipse" is common.

NOTE1: See this Wikipedia article https://en.wikipedia.org/wiki/Trammel_of_Archimedes