Common misspelling of "
minuscule" (meaning "very small").
In fact, this
spelling is now so common that it is
generally accepted as merely an "
alternative spelling". Even though old
Webster 1913 won't accept it, later
dictionaries often will; the Ninth
Edition of the
Concise Oxford Dictionary (1995)
lists it as simply a "
variant spelling", and so has
Merriam-Webster's Collegiate Dictionary done in all editions
published since 1971.
Merriam-Webster's Dictionary of English Usage (1989) has (amongst other things) the following to say about the word, which may be of some interest:
"It may be, in fact, that miniscule is now the more common form. An article by Michael Kenney in the Boston Globe on 12 May 1985 noted that miniscule outnumbered minuscule by three to one in that newspaper's data base."