"Nay" is a word that can be used in different ways, depending on the context. Here are some of its meanings:

• Adverb: It can be used to correct what has just been said by replacing a word with one that is more accurate or appropriate. For example, "I was angry - nay, furious - at the way they were treating that poor dog".
• Noun: It can be used to refer to a negative vote or a person who votes "no". For example, "when the votes were tallied, it was 241 yeas and 54 nays".
• Conjunction: It can be used to mean "not only that but also" or "indeed". For example, "many good, nay, noble qualities".
• Old-fashioned or dialect: It can be used as a substitute for "no". For example, "Nay, I do not wish to go".

In summary, "nay" can be used to express disagreement, correction, or emphasis.