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
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
Stan