reptation

Century Dictionary and Cyclopedia

1. n. The act of creeping or crawling on the belly, as a reptile does.
2. n. In mathematics, the motion of one plane figure around another, so as constantly to be tangent to the latter while preserving parallelism between different positions of its own lines; especially, such a motion of one figure round another precisely like it so that the longest diameter of one shall come into line with the shortest of the other. This motion was applied by John Bernoulli in 1705 to the rectification of curves. Let AB he a curve whose length is required; let this be reversed about its normal, giving the curve ABC, and let this be reversed about the line between its extremities, giving the spindle-shaped figure ABCD; let DEFG be a similar and equal figure turned through a right angle—then, if the first has a reptatory motion about the second, its center will describe a four-humped or quadrigibbous figure OPQRSTUV, with humps at P, R, T, V. Let this be placed in contact with a similar and equal figure so that a maximum and minimum diameter shall coincide, and receive a reptatory motion, then its center will describe an octogibbous or eight-humped figure. By a similar process, this will describe a sixteen-humped figure, etc. Each of these figures will have double the periphery of the preceding, and they will rapidly approximate toward circles. Hence, by finding the diameters of each, we approximate to the length of the original curve.

Wiktionary

1. n. creep
2. n. physics A creeping thermal motion of entangled linear polymers

GNU Webster's 1913

1. n. (Zoöl.) The act of creeping.