An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

(v.tr.) To change or make different.
(v.intr.) To change or become different.

M.E. alteren, from O.Fr. altérer, from M.L. alterre, from L. alter "other," from PIE *al- "beyond" + comp. suffix -ter.

Degargun kardan, degargunidan, from degargun, from degar, → change, + -gun "manner, fashion," → elliptical, + kardan, -idan, → -ize.

1) The act or process of altering; the state of being altered.
2) The result of altering.

Verbal noun of → alter.

1) Happening or following in turns; succeeding each other continuously.
2a) (v.intr.) To occur in a successive manner (day alternates with night); To change back and forth from one state, action, or place to another.
2b) Electricity: To reverse direction at regular intervals in a → circuit.
3) (v.tr.) To do or execute in succession or one after another (to alternate work and rest).

From L. alternus "one after the other," p.p. of alternare "to do first one thing, then the other," from alternus "every other," from alter "the other".

1) Peyvâr from pey "step; after" (as in peyâpey "successively, repeatedly") + Pers. vâr "turn (succession), time (repetition), alternation". Compare with Skt. vâra "one's turn, appointed time, alteration, succession".
2, 3) Peyvâr šodan, peyvâr kardan, peyvâridan, verbs from peyvâr "alternate," as above.

Occuring in a successive manner. Acting or proceeding by turns. → alternating current.

Verbal adj. from → alternate; → -ing.

An → electric current that reverses direction of flow at regular intervals. The typical alternating current is → sinusoidal in shape. Alternating current has the advantage over → direct current in that its → voltage magnitude can be changed easily through a → transformer. Moreover, it is safer to transfer over the longer city distances and can provide more → power. The frequency of alternating current is 50 Hz (Europe) or 60 Hz (USA).

→ alternating; → current.

General: Successive change from one thing or state to another and back again.
The process of periodically varying a voltage from zero to a maximum, back to zero, to a minimum, and then to zero.

Alternation, noun from → alternate.

1) (n) A proposition or situation offering a choice between two or more things only one of which may be chosen.
2) (adj) Offering or expressing a choice. → alternative energy, → alternatively.

Alternative, from → alternate.

Degarine, from degar "other," variant digar, from Mid.Pers. dit, ditikar "the other, the second," O.Pers. duvitiya- "second," Av. daibitya-, bitya- "second," Skt. dvitiya- "second," PIE *duitiio- "second" + suffix -ine.

Energy from a source other than the conventional fossil fuel sources.

→ alternative; → energy.

Statistics: In → significance testing, any hypothesis which differs from the one being tested. A hypothesis alternative to the → null hypothesis is denoted by H₁.

→ alternative; → hypothesis.

In place of, or as an alternative to.

Adverb from → alternative.

A machine or device that produces alternating current.

Alternator, noun from → alternate + → -or.