The footnote that you reference is actually on page 9 of the cited reference.

And the footnote should be taken in context: 'At this time Nelson was commanding a small force of three warships...each carrying seventy-four guns, as well as three frigates, which were more lightly armed vessels...but were faster, more maneuverable and ideal for scouting purposes. This was a stronger squadron [this is where the subject footnote is used] than would normally be sent on a reconnaissance mission, and although if might hamper the sailing of the French fleet from Toulon, it could not stop it.'

The authors in the passage clearly delineates between a fleet and a squadron, and the attached footnote actually does not support the text.

So, even by the secondary source you referenced here, there is a definite difference in the Royal Navy, between a fleet and a squadron.