Antedating o'the day for the Historical #Dictionary of #ScienceFiction: one of my favorite entries, "eyetracks", (imaginary?) marks left on a book by the act of reading it. From 1952 to '49 (plus another '52 referring to art rather than books: tweaked def for this).

https://sfdictionary.com/view/1886/eyetracks

Historical Dictionary of Science Fiction: eyetracks

Historical Dictionary of Science Fiction