I don't know about tire, but they mentioned unicorn too, and unicorn means rhinoceros in this context. you can look it up in any 19th c. dictionary. real unicorn is lycorn - French still use this word. according to linguistics these are so called semantic shifts, it's when a word changes its meaning to a new one. however, I always thought it has to be a common word, and the shift would happen through slang. were unicorns and rhinos discussed so widely among the visitors of English pubs, that people got them mixed up? perhaps I don't understand the nature of semantic shifts, but this seems unlikely.
I don't know about tire, but they mentioned unicorn too, and unicorn means rhinoceros in this context. you can look it up in any 19th c. dictionary. real unicorn is lycorn - French still use this word. according to linguistics these are so called semantic shifts, it's when a word changes its meaning to a new one. however, I always thought it has to be a common word, and the shift would happen through slang. were unicorns and rhinos discussed so widely among the visitors of English pubs, that people got them mixed up? perhaps I don't understand the nature of semantic shifts, but this seems unlikely.