Close but not exactly. Windows 5 was 2000, Windows 5.1 was Windows XP.

But it’s more confusing than that because of the two different lines: the MS-DOS based line which covered Windows 1.0 through ME, and the multi-user NT line for workstations and servers which adopted the same version numbers as the currently released MS-DOS line that was available at the same time. I.E. windows NT 3.1 used the windows 3.1 UI from the DOS line, but was New-Technology instead of DOS under the hood. NT4 used the DOS based win95 UI, and NT5 was Windows 2000 also with the familiar Windows 9x UI. Everything since XP has been exclusively NT under the hood.