You still receive security updates for all manjor MacOSes, so albeit lack of proper naming you can assume each new release as LTS.

Small, but important detail: you receive some security updates, not all. Same with iOS.

Every release is an LTS version, with support for about 8 years.

The current stable release of macOS (10.14 Sonoma) supports all Macs introduced in 2017 and later.

Older macOS versions don't receive all security fixes, so while you'll receive security updates from time to time, the OS isn't fully patched. It's a bit different from, say, Ubuntu LTS.