Rebi

We have a letter which begins thus: “I send you herein twenty geographical rebi [we prefer the rebuses. Ed.], two proverbial, twenty enigmas, seven square words.”

Source: wiktionary

“A puzzle bee. Each of you four girls could prepare an original puzzle in private, and to-morrow night we could all meet in the sitting-room, the puzzles could be read off one at a time, and we could try to guess them.” / “You mean square words, charades, beheadings, and rebi?” / “‘Rebi’ for the plural of ‘rebus’ is good,” said Uncle Frank, laughing. “Yes, that’s what I mean,[…]”

Source: wiktionary

Michael Preston has dubbed this form of riddle the "chemical rebus" (1982:117).[…]Meanwhile, down in the freshman chemistry office, scores of these same rebi are posted on a billboard for another purpose. Undergraduates use chemical rebi to play with recently acquired knowledge, sometimes to affirm a conceptual mastery which is exceedingly difficult.

Source: wiktionary

Mary is the present editor of their monthly publication, The Enigma, from which the rebi in this article were taken. The rebus is the same as the Loony Logo in principle, but differs in economy (a good rebus contains many fewer letters) and hence in content (any word or group of words is rebus material, but most common phrases cannot be readily rebized). There is overlap, of course; February's GSEG = scrambled eggs and PIPRE = Pied Piper are venerable rebi.

Source: wiktionary