Green’s Dictionary of Slang

horn n.1

[the obvious link is to horn n.2 (1a), the penis, but the term apparently comes from an old German farming practice of grafting the spurs of a castrated cock on the root of the severed comb. These transplants would grow into horns, sometimes several inches long. The German word hahnreh or hahnrei, meaning cuckold, orig. meant capon, a castrated cock; an older theory took the posture of ‘missionary position’ intercourse, in which the man represented a head and the woman’s legs, spread and raised, were his horns; thus note Ward, ‘The Dancing School’ (1700): ‘I should hate a Husband with horns, were they even of my own grafting’]

[mid-15C+] an all-purpose term for cuckoldry, a symbol of cuckoldry; usu. in pl.

In compounds

horn-child (n.)

[20C+] (W.I.) the offspring of an adulterous relationship.

horn fair (n.)

see separate entry.

horn-grower (n.) (also horn-merchant)

[18C–19C] a married man.

horn-headed (adj.)

[18C] cuckolded.

horn-maker (n.)

[late 16C–17C] one who cuckolds.

horn work (n.)

[early 17C–mid-19C] cuckoldry; also attrib.

In phrases

blow one’s horn (v.)

[early 18C] to be a cuckold, to be cuckolded.

give horns (v.)

[19C+] to cuckold.

grow horns (v.) (also bud horns)

[17C–18C] to become the victim of cuckoldry.

horns-to-sell (n.) [18C–19C]

1. a promiscuous wife.

2. a cuckold.

plant horns (v.)

[mid-18C] to make someone into a cuckold.

put horns on (v.)

[1950s] to make someone into a cuckold.

put the horns on (v.) [fig. use] [1940s+] (US)

1. to jinx.

2. to cuckold.

take a horn (v.)

[20C+] (W.I.) to accept that one’s partner is having/has had an affair without making an issue out of it.

wear (the) horns (v.)

[17C+] to be cuckolded.