explain clamp in css code example

Example 1: clamp css

font-size: clamp(1rem, 2.5vw, 2rem);
font-size: clamp(1.5rem, 2.5vw, 4rem);
font-size: clamp(1rem, 10vw, 2rem);

Example 2: css clamp

width: clamp(400px, 60vw, 600px);

div {  
  font-size: clamp(1.1rem, 0.7153rem + 1.6368vw, 1.5rem);
}

.logo {    
  width: clamp(350px, 75%, 800px);    
}
And the font’s CSS is:
.title {     
  font-size: clamp(1.5rem, 5vw, 4rem);  
}