Question: both is what part of speech?
Answer: both ​Definitions and Synonyms ​‌‌‌ as a determiner (followed by a noun, but not by a pronoun): Both children are at school. as a predeterminer (followed by a word such as 'the', 'this', 'his' etc): I like both these pictures. Both her children are boys. ... (following a pronoun object): I like them both.