Physical partition is a concept from partition tables using msdos type, which supports only 4 physical partitions, but can have 3 physical and 1 extended, with several logical partitions. This is a way to devide a disk into multiple units.

What is physical partitioning?

When you add a physical volume to a volume group, the physical volume is partitioned into contiguous, equal-sized units of space called physical partitions. A physical partition is the smallest unit of storage space allocation and is a contiguous space on a physical volume.

What is in Linux partition?

Disk Partitioning in Linux

In most cases, large storage devices are divided into separate sections called partitions. Partitioning also allows you to divide your hard drive into isolated sections, where each section behaves as its own hard drive.