Eroteme

1858, Goold Brown, The Grammar of English Grammars, fourth edition, Samuel S. and William Wood, page 798, The value of the eroteme as a sign of pause, is stated very differently by different grammarians.... J.S. Hart avers, that, "A question is reckoned as equal to a complete sentence, and the mark of interrogation as equal to a period."

The note of interrogation or eroteme is used at the end of a sentence to designate (1) a single question or (2) more, and (3) is sometimes written in parentheses to express a doubt or challenge the accuracy of a statement.

On the typewriter keyboard, just below the question mark (the eroteme, note of interrogation, or uncertainty sign), there appears a short, slanting stroke […]