I've written a bit on this subject, as some of you know.
There are all sorts of appellations given to these revolvers - and a number of opinions.
Going by frame size - and 'not' barrel length is what probably defines the true 'pocket pistol'.
The old criteria that 'if it fits in a pocket' doesn't wash.
A 'belt' pistol was just that - a revolver designed to be carried in a holster.
The smaller-framed Colts were really designed to be carried on the person - but not openly.
In the book - 'The Book of Colt Firearms' - by Sutherland and Wilson - judged by all serious Colt collectors to be the 'bible' - under 'Pocket Colt Percussion Arms' you'll see indexed on page 602:
No. 1 Paterson Model
No. 2 Paterson Model
Baby Dragoon or Model 1848
Model 1849
Sidehammer Model 1855
Model 1862 Pocket Pistol of Navy Caliber
Model 1862 Police
There are sub-titles for Conversions, London Models and Experimentals, as well, and a bit lower, you'll see:
Pocket, New, DA Model Revolver (marketed in 1893)
Pocket Positive DA Model Revolver (marketed in 1908)
Nowhere does a reference show that barrel length had anything to do with description.
A large-frame such as a Schofield or the 'Avenging Angel' used by the Mormon Danite assassins (Porter Rockwell didn't have the only one) were 'belly guns' - short-barrelled, large-bore concealment revolvers.
Vaya,
Scouts Out!