While researching using the 1841 Scottish Census I came across the abbreviation "F S" under profession. As I was not sure what this was I did a quick search online and came across this useful list of commonly used abbreviations in a rootschat.com forum here.
These are the official abbreviations used in the censuses:
Ag. Lab. 1841-81 Agricultural labourer
Ap. 1841-61 Apprentice
Army 1841 Members of HM land forces of whatever rank
Cl. 1841-61 Clerk
FS. 1841 Female servant
H.P. 1841 Members of HM armed forces on half-pay
HLW 1841 Hand loom weaver (followed by silk, cotton etc for material they work in)
FWK 1841 Frame work knitter
Ind. 1841 Independent - people living on their own means
J. 1841 Journeyman
M. 1841 Manufacturer
m. 1841 Maker - as in 'Shoe m.'
MS 1841 Male servant
Navy 1841 Members of HM naval forces, including marines,
of whatever rank
P. 1841 Pensioners in HM armed forces
Rail Lab. 1851 Railway labourer
Serv. 1861 Servant
Sh. 1841 Shopman
Are there any others that you know of?