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

1) To reduce in force, value, amount, or degree. → attenuation, → attenuation factor.
2) To reduce the amplitude of an electrical signal with little or no distortion.

L. attenuatus, p.p. of attenuare "to make thin," from → ad- "to" + tenuare "make thin," from tenuis "thin;" cf. Gk. tanaos "thin, slender, elongated;" Skt. tanuka-, tanu- "thin;" Av. tan- "to stretch;" Pers. tonok "thin," as below; O.Ir. tanae "delicate, thin;" O.H.G. dunni "thin."

Tonokidan, from tonok "thin, slender, slight, tender, delicate" + -idan, infinitive suffix. Tonok, from Mid.Pers. tanuk, Av. root tan- "to stretch, extend," cognate with L. tenuis, as above.