What is the different between rf, sf, fz, sfz

[dora96]

Sometimes, I am confused with this above term. I sort of know it but not really understand. At the moment, I am learning Beethoven pathetique. There is some in the song. How hard or accento I need to play to make the different from one to the other. It will be nice to actually hear someone play it and see the difference

[spaciiey]

rf = rinforzando - reinforced, but not as much as the accent
sf = sforzando - sudden strong accent on a note or chord
fz = forzando - the sharp accenting of a note/groups of notes
sfz = the same as sf

[thalberg]

and don't forget pf

means 'poco forte'- a little louder.  Brahms uses it.

[soderlund]

So, thalberg, there is no opposite to fp, forte piano, from forte to piano immideately? If I saw pf, I would think from piano to forte immideately. But do you only right forte subito, or is there actually a combination for this?