An Etymological Dictionary of Astronomy and Astrophysics

1a) The bony pointed outgrowth, usually in pairs, on the heads of some animals.

1b) Astro.: Either of the ends of the → crescent Moon.

2. Something resembling a horn.
   

3. A wind instrument, originally an animal horn used as a wind instrument.
   

See also: → feedhorn

Etymology (EN): M.E. horn(e), from O.E. horn “horn of an animal,” also “wind instrument” (originally made from animal horns), from P.Gmc. *khurnaz (cf. Ger. Horn, Du. horen), from PIE *ker- “head, horn, top, summit” (cf. Pers. soru “horn,” sar “head,” Gk. kara “head,” karena “head, top,” keras “horn;”
L. cornu “horn,” cerebrum “brain;” Skt. śiras- “head, chief”).

Etymology (PE): 1, 2) Mid.Pers šâk; cf. Skt. sakha- “a branch, a limb;” Arm. cax; Lith. šaka; O.S. soxa;
PIE *kakhâ “branch.”

3. Karnâ “a trumpet-like wind instrument,” variant sornâ “a wind instrument,” probably related to soru, sorun “horn,” sar “head;” Mid.Pers. sar “head,” sru “horn;” Av. sarah- “head,” srū- “horn, nail;” cognate with E. horn, as above, from PIE *ker- “head, horn.”