Terminology
The term lower case originated in the early days of the printing press used with movable type in letterpress printing. The individual type blocks used in hand typesetting are stored in shallow wooden or metal drawers, known as cases, with subdivisions into compartments known as boxes to store each individual letter. In many countries the majuscules and minuscules are stored separately, with a pair of boxes for each typeface at a specific size. For typesetting, the two cases are taken out of the storage rack and placed on a rack on the compositor's desk. By convention, the case containing the capitals (and small capitals) stands at a steeper angle at the back of the desk, with the case for the small letters, punctuation and spaces, at a shallower angle below it to the front of the desk, hence upper and lower case. The term "upper case" is a backformation and not used by printers to classify capital letters. The upper case contained accented letters, numbers and capital ligatures in addition to capital letters and comes from the antique age of setting type for printing presses, when printers kept the type for these letters in the upper drawers of a desk or in the upper type case, while keeping the type for the more frequently-used smaller letters in the lower type case within easy reach.
Various patterns of cases are available, often with the compartments for lower-case letters varying in size according to the frequency of use of letters, so that the commonest letters are grouped together in larger boxes at the centre of the case. The compositor takes the letter blocks from the compartments and places them in a composing stick, working from left to right and placing the letters upside down with the nick to the top, then sets the assembled type in a galley.
The Oxford Universal Dictionary on Historical Advanced Proportional Principles (reprinted 1952) indicates that this usage of "case" (as the box or frame used by a compositor in the printing trade) was first used in 1588. Originally one large case was used for each typeface, then "divided cases", pairs of cases for upper and lower case, were introduced in the region of today's Belgium by 1563, England by 1588, and France before 1723. Though pairs of cases were used in English-speaking countries and many European countries, in Germany and Scandinavia the single case continued in use.
For paleographers, a majuscule script is any script in which the letters have very few or very short ascenders and descenders, or none at all (for example, the majuscule scripts used in the Codex Vaticanus Graecus 1209, or the Book of Kells).
The word minuscule is often spelled miniscule, by association with the unrelated word miniature and the prefix mini-. This has traditionally been regarded as a spelling mistake (since minuscule is derived from the word minus), but is now so common that some dictionaries tend to accept it as a nonstandard or variant spelling. However, miniscule is still less likely to be used for lower-case letters.
Read more about this topic: UPPERCASE