PHP: define() vs const — what's the difference and which is better to use?

Hello everyone! I've been writing PHP for about a year, and one question constantly bothers me. I see that in different projects constants are declared differently: some use define(), others use the const keyword. For example, in old frameworks I often see this code: ```php define('DB_HOST', 'localhost'); define('DB_NAME', 'mydb'); ``` And in modern projects on Laravel or Symfony — this: ```php class Config { const API_KEY = 'abc123'; const TIMEOUT = 30; } ``` Or even just in the global scope: ```php const MAX_USERS = 100; ``` I read PSR-1 and PSR-12, but they are quite vague. It seems like const is recommended, but it doesn't explain why. I tried both options — and both work. But I'm confused that define() allows setting constants inside if blocks, while const does not. And I also heard that in new versions of PHP const has become faster. Is this true? Please advise, in which situations which method is better? Are there any practical