Minuscule’s main use is as an adjective meaning tiny or insignificant. It can also mean written in minuscule (= minuscular), referring to a small cursive mediaeval script. Minuscule as a noun can refer to this palaeographic writing or simply to a lowercase letter.* But its general use as an adjective is what we usually encounter, and it’s the variation in its spelling (minuscule or miniscule) that interests me here.
The word comes from French minuscule, from Latin minusculus, fem. minuscula, as in minuscula littera, ‘slightly smaller letter’. Minuscula is formed by adding the diminutive suffix -cule to minus, neuter of minor — ‘less, smaller’ — from Proto-Indo-European *mei-, ‘small’. The common prefix mini- has probably lent minuscule a folk etymology that influences its contemporary spelling: miniscule is a popular variant. Pronunciation might also have played a part.
Here are some examples of miniscule I’ve come across in books:
There is even a miniscule dance floor for the perpendicular manifestations of horizontal intentions (Hugh Leonard, A Peculiar People)
Only in the microscopic domains of the atom, or the vast reaches of interstellar space, do miniscule discrepancies between nature according to Newton and nature according to Nature make themselves known. (Ian Stewart, Does God Play Dice? The New Mathematics of Chaos)
hiragana […] often, in miniscule writing, glosses obscure kanji to help the reader (Steven Roger Fischer, A History of Language)
Miniscule occupies a grey area of legitimacy and is likely to attract criticism. Some call it non-standard; others dismiss it as an error. Bryan Garner rejects it, MWDEU doesn’t, while The Columbia Guide to Standard American English sits on the Fence of Judgement but advises the uncontroversial spelling minuscule. The OED says miniscule is ‘very common but regarded as erroneous’; Oxford Dictionaries considers it an acceptable variant.
Unless you’re prepared to argue miniscule’s case, you’re better off avoiding it. If you want to remember the more correct form, think of its old association with minus, or tell yourself that minuscule is preferred by us.
* Its counterparts are majuscule (n., adj.) and majuscular (adj.).