2. That which guides, points out, informs, or directs; a pointer or a hand that directs to anything, as the hand of a watch, a movable finger on a gauge, scale, or other graduated instrument. In printing, a sign used to direct particular attention to a note or paragraph; called also fist.
4. A prologue indicating what follows.
6. (Science: mathematics) The figure or letter which shows the power or root of a quantity; the exponent. [In this sense the plural is always indices] index error, the error in the reading of a mathematical instrument arising from the zero of the index not being in complete adjustment with that of the limb, or with its theoretically perfect position in the instrument; a correction to be applied to the instrument readings equal to a4e
the error of the zero adjustment. Index expurgatorius. [L] see index prohibitorius (below). Index finger. See index. Index glass, the mirror on the index of a quadrant, sextant, etc. Index hand, the pointer or hand of a clock, watch, or other registering machine; a hand that points to something.
(Science: mathematics) index of a logarithm, a catalogue of books which are forbidden by the church to be read; the index expurgatorius [L], or expurgatory index, is a catalogue of books from which passages marked as against faith or morals must be removed before Catholics can read them. These catalogues are published with additions, from time to time, by the Congregation of the index, composed of cardinals, theologians, etc, under the sanction of the pope. Index rerum [L], a tabulated and alphabetized notebook, for systematic preservation of items, quotations, etc.