On the meaning of ``single-space'' inter-line spacing

[Ludovic Courtès]

Hi,

People often refer to ``single-space'' or ``double-space'' inter-line
spacing, but what does it mean exactly?

Implicitly, it is relative to the font size.  But for instance, in Lout
terms, 1.0fx (which is single-space, strictly speaking) is clearly too
tight, while 1.2fx seems more appropriate.

Is there a widely accepted definition of ``single-space'', or is it just
imprecise wording?

Thanks,
Ludovic.