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

1) To cut, bite, or corrode with an acid or the like; engrave with an acid or the like, as to form a design in furrows that when charged with ink will give an impression on paper.
2) To produce (a design, image, etc.) by this method, as on copper or glass (Dictionary.com).
3) Astro.: To cut or corrode an → iron meteorite with a strong → acid to reveal its hidden → crystalline structure.

From Du. etsen, from Ger. ätzen "to etch," from O.H.G. azzon "to cause to bite, feed," ultimately from PIE root *ed- "to eat;" cf. Av. ad- "to eat;" Mod.Pers. âš "thick brew, soup" (from O.Pers. *āšyā-, Proto-Ir. *HasH- "to eat"); Skt. ad- "to eat;" Gk. edo "I eat;" Lith. edu "I eat;" O.Irish ithim "I eat;" O.E. etan, O.H.G. essan, Ger. essen "to eat."

Bâ tizâb kandan, literally "to dig with acid," from bâ "with," tizâb "acid," kandan "to dig;" ecidan, from E. etch, cognate with Pers. âš, as above.

1) The act or process of making designs or pictures on a metal plate, glass, etc., by the corrosive action of an acid instead of by a burin.
2) An impression, as on paper, taken from an etched plate.
3) The design so produced (Dictionary.com).
4) The act or process of cutting a smooth cross section of a → meteorite with → acid to reveal its → crystal structure.

Verbal noun of → etch.

To make something longer or wider by pulling it.

M.E. strecchen, from O.E. streccan; cf. Dan. strække, Sw. sträcka, O.Fris. strekka, O.H.G. strecchan, M.L.G., M.Du., O.H.G., Ger. strecken "to stretch"), perhaps a variant of the root of stark, or from PIE root *strenk- "tight, narrow; pull tight, twist," → strain.

Dargidan, from darg "long" (Zâzâ, Ossetic), variants derâz, derež "long" (→ longitude); Mid.Pers. drâz "long;" O.Pers. darga- "long; " Av. darəga-, darəγa- "long," drājištəm "longest;" cf. Skt. dirghá- "long (in space and time);" PIE *dlonghos- "long."

The second term of the right-hand side in the → induction equation. This term is at the origin of the → dynamo effect and also of the → Alfven waves when in the presence of a mean field.

→ stretch; → term.

The stretching of an object under → tidal force. Tidal stretching results from a difference in the gravitational pull felt on two sides of a body. It is proportional to the inverse cube of the distance to the source of gravity (1/r³). As a consequence, nearby objects, even small ones like the Moon, raise high tides, whereas distant giants like Jupiter do not produce much of an effect.

→ tidal; → stretching.