What is death?

I find some scriptures really confusing.

The bible uses the word death or dying in a number of places and it is not always clear whether it’s talking about physical death, spiritual death, eternal separation, decay, what happens to our old man when we accept Christ.

I’m not a studier of Greek or Hebrew, so I have no idea what word is being used and in what context other than from the translation provided by hopefully learned folk who have attempted to translate the text faithfully into a language I sort of understand.

This morning then I was reading in John 8. There is a discussion between Jesus and the Jews which culminates in Jesus explaining that not only does he know Abraham (despite being less than 50 years old) he has spoken with him. [Presumably eluding to eternal life and to recognisable states of existence in the after earthly life]

So far so good…

But the bit that confuses is what is to be understood by John 8:52

⁵²The Jews said to him, "Now we know that you have a demon! Abraham died, as did the prophets, yet you say, 'If anyone keeps my word, he will never taste death.'

• Are they talking about the same death?
• Is Jesus suggesting that people who hold to His teaching never cease to breath the air of this blue/green sphere?
• Is the death we won’t taste that Jesus is suggesting the same as the one in Matthew 16:28?
• Or what about Hebrews 2:9? What death did Jesus suffer for all of us so that we don’t all have to ‘taste death’?