This is standard definition in case of SATA disks, NVM, SSD each have own defined partition names if so to be called, this is based on the number of disks you use in your environment.
For example if you would have a setup with NVM disks the namming will be different yet the names again will be defined by the physical number of disks visible to host.
root@sc:~# fdisk -l
Disk /dev/sda: 446.6 GiB, 479559942144 bytes, 936640512 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: dos
Disk identifier: 0xcc24555f
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 4096 1050623 1046528 511M 83 Linux
/dev/sda2 1050624 457766911 456716288 217.8G 83 Linux
/dev/sda3 457766912 458813439 1046528 511M 82 Linux swap / Solaris
/dev/sda4 458813440 936630271 477816832 227.9G 83 Linux
Disk /dev/sdb: 1.8 TiB, 1999844147200 bytes, 3905945600 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Now as you can see I have here 2 disks in use, SDA a SSD in this case and SDB a SATA disk. SSD/sda is used for OS while sdb its pure storage.
Hope this clears out the fog.