The spelling of the name "Tom Blair" can be explained using the International Phonetic Alphabet (IPA). "Tom" is pronounced as /tɒm/ with a short "o" sound and an unaspirated "t". "Blair" is pronounced as /blɛər/ with a long "a" sound as in "share". The "ai" represents the diphthong /ɛə/ which sounds like the letters "a" and "i" combined. The "r" is pronounced with a slight roll or tap. Together, "Tom Blair" is spelled phonetically as /tɒm blɛər/.
The phrase "Tom Blair" does not have an etymology as it does not correspond to a word or phrase with a definitive origin or history. However, if you are referring to a specific person named Tom Blair, it would be necessary to have more information to determine the etymology of their name, such as their cultural background or any relevant historical context.