1. The act of inverting, or turning over or backward, or the state of being inverted.

2. <mathematics> A change in the order of the terms of a proportion, so that the second takes the place of the first, and the fourth of the third.

3. <genetics> An aberration in which a chromosomal segment is deleted and reinserted in the same place but turned 180 degrees from its original orientation, so that the gene sequence for the segment is reversed with respect to that of the rest of the chromosome.

4. <geometry> A peculiar method of transformation, in which a figure is replaced by its inverse figure. Propositions that are true for the original figure thus furnish new propositions that are true in the inverse figure. See Inverse figures, under Inverse.

5. Said of intervals, when the lower tone is placed an octave higher, so that fifths become fourths, thirds sixths, etc. Said of a chord, when one of its notes, other than its root, is made the bass.

6. <geology> The folding back of strata upon themselves, as by upheaval, in such a manner that the order of succession appears to be reversed.

7. <chemistry> The act or process by which cane sugar (sucrose), under the action of heat and acids or ferments (as diastase), is broken or split up into grape sugar (dextrose), and fruit sugar (levulose); also, less properly, the process by which starch is converted into grape sugar (dextrose).

The terms invert and inversion, in this sense, owe their meaning to the fact that the plane of polarization of light, which is rotated to the right by cane sugar, is turned toward the left by levulose.

See: invert.

Origin: L. Inversio: cf. F. Inversion.

(04 Jul 1999)