pt
The typographic point: 1/72 of an inch, longtime resident of the type shops.
One pt is 1/72 of an inch — the point Anglo-American typography standardized long before screens, and that word processors taught everyone: 12 point, 11 point. In CSS arithmetic, 12pt and 16px are exactly the same length.
It is the right choice in print stylesheets, where the graphic trade has spoken point fluently for centuries. On screen, it is an expensive synonym for px that tends to give away CSS ported from an office document.
12pt = 16px
@media print {
body {
font-size: 11pt;
}
}