What is zero trust?
Zero trust is the security model that stops treating the network location as proof of anything. Instead of "inside the office network, therefore trusted", every request is authenticated and authorised on its own: who is the user, what device, is it healthy, and is this specific access allowed. The old model breaks the moment one thing inside the perimeter is compromised; zero trust assumes that has already happened.
What it looks like in practice
MFA everywhere, device health feeding access decisions (an unencrypted or unpatched machine gets less access), per-application access instead of flat VPN reach, and admin rights granted narrowly rather than broadly. Nobody buys "a zero trust"; it is a direction existing tools move in, and vendors stamp the phrase on everything, so judge products by what they check per request rather than the label.