Adoption by arms.
An ancient custom of giving arms to a person
of merit, which laid him under the obligation of being your champion
Adoption by baptism.
Being godfather or godmother to a child. The child by baptism is
Adoption by hair.
Cutting off your hair, and giving it to a person in proof that you
receive him as your adopted father. Thus Boson, King of Arles, cut off
his hair and gave it to Pope John VIII, who adopted him.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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