Hi,

  
There are two similar terms, 'plenum', and 'ripieno'.
Neither of them mean 'all', rather they refer to all
stops (starting at 8' and up) of a same family, or
a combination that includes (almost) all harmonics
of an 8'.
    

IIRC there are two further terms called "plein jeux" (all stops of the 
principal family like prestants, montres, octaves etc.) and "Grand Jeux" 
(adding the reeds to plein jeux?!?).

IMO all those names may describe different things, depending on the instrument 
the composer was using. If your instrument has no montre 8', "plein jeux" 
would probably include an 8' flute. And if you have no reeds at all, 
maybe "Grand Jeux" then means a "plein jeux" plus an tertiary aliquot (like 
tierce etc.) to fake the missing reeds?

Best regards,

ce
Perhaps I can clarify a bit of the terminology.

"Plenum" or "In organo pleno" and "Ripieno" come from the German Baroque era. They mean a full Principal chorus (Prestants, Octaves, Quint 2 2/3', not 5 1/3' !, Mixtures), combined with some Flute stops (Quintaton 16', Flute 8'), and depending on the character of the piece, one or more manual Reeds. In the Pedal you have to draw the strong Reeds like Posaune 16'.
In later time, say Reger c.s., this term is used as the final, strongest sound and that quite equals the "Tutti", then meaning full organ but of course, as pointed out earlier without undulating stops and without some very soft charachteristic stops. Usually also without Flute's 4' (on a real organ a Flute 4' only consumes a lot of air and adds practically nothing to the Tutti)

"Plein jeu" and "Grand jeu" are stemming from the French Baroque music.
In a "Plein jeu" you have the principals ( on a 16' basis), bourdon 8' and all the different mixtures (Cymbale etc.); no reeds. In the pedal only a Trumpet 8', coupled to the manuals; French organs from this peroid had no other pedal stops.
In a "Grand jeu" you have the Trumpets, Clairons (4') plus tertiary aliquots like Cornet or Sesquialter; no principals or bourdons.

"Tutti" in French romantic music (and later) means all manuals coupled, with foundations (principals, flutes etc.), mutations and reeds and sub- and supercouplers. No undulating stops and no soft charachteristic stops like Voix humaine, quite similar to the German romanitcism. Only the sound is very different: in French organs the Reeds are very strong and dominant and the Mixtures are quite soft in comparison; in German organs from this time the Reeds are fairly weak and the upperwork is stronger.

Kind regards,
Bert