Yes, terminology in Word is often confusing. :-(

In addition, control over some aspects of formatting is minimal. Unlike some page layout programs, Word doesn't let you specify what Line Spacing set to (for example) 1.5 actually means. Instead, 1.5 simply means 50% more than "Single," and "Single" isn't well-defined either (it depends on the selected font and the printer).

The only fixed value is "Exactly" which implies that you should set a fixed value in points.

Of course it is OK to ask for clarifications. This is a rather friendly forum, I think. :-)

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional