I have recently surveyed around one hundred different papyrological and text-critical studies to see how scholars spell the word used to signify a scribal marking “above the line.” This could refer to a variety of things, including a horizontal stroke placed over abbreviated words and numbers, expunging dots above a letter, a letter serving as a correction or addition above another one on the line, etc. There are two spellings of this commonly used word in the literature: 1) superlinear and 2) supralinear. In the sample of literature I scanned, both spellings occur almost equally. In many cases, the terms are used interchangeably within the same text. It seems to me that it is time we decide on one of the terms.
The prefixes super and supra are both derived from Latin roots meaning “above” and “over,” among other things, and the former is a far more common prefix in the English language (e.g., superstructure, superpower, supernatural, superabundant, etc.). “Superlinear” (and to a far less degree, “supralinear”) is a technical term that is commonly employed in mathematics and physics, and so I would suggest that papyrologists use the term “supralinear” in contradistinction to the former. Of course we all known what both of the terms mean in papyrological contexts, but I think we should aim at terminological uniformity in our grammars, textbooks, papyrological editions, and essays in order to avoid any possible confusion. It might be valuable to trace the origin and development of this term within the discipline and to provide a more precise analysis of the Latin prefixes super and supra vis-à-vis the meaning they are intended to convey. This is a provisional suggestion and I welcome your comments.