An Etymological Dictionary of Astronomy and Astrophysics

Math.: A rearrangement of the elements of a set in a particular order. The number of permutations of n objects is equal to n! (→ factorial n). For example, there are 24 permutations of letters A, B, C, and D (4! = 1 × 2 × 3 × 4). The number of permutations of n objects taken r at a time is denoted by ⁿP_r and equals n! / (n - r)!. For example, the number of permutation of A, B, C, and D taken two at a time is 12. If n objects are of k different kinds, with r₁ alike of one kind, permutations of n objects equals n! / r₁! r₂! … r_k!, where r₁ + r₂ + … r_k = n.

Etymology (EN): Verbal noun of → permute.

Etymology (PE): Permuteš, verbal noun of → permute.
Jâygašt , from jâ “place”
(from Mid.Pers. giyag “place;” O.Pers. ā-vahana- “place, village;” Av. vah- “to dwell, stay,” vanhaiti “he dwells, stays;” Skt. vásati “he dwells;” Gk. aesa (nukta) “to pass (the night);”
Ossetic wat “room; bed; place;” Tokharian B wäs- “to stay, wait;” PIE base ues- “to stay, live, spend the night”) + gašt past tense of gaštan, gardidan “to turn, to change” (Mid.Pers. vartitan; Av. varət- “to turn, revolve;” Skt. vrt- “to turn, roll,” vartate “it turns round, rolls;” L. vertere “to turn;” O.H.G. werden “to become;” PIE base *wer- “to turn, bend”).