Rolandspeak... (terminology for newbies)

Dear Andrew,

Could you please briefly explain the following Rolandspeak terms? (in brackets is what I can make out, probably completely wrong...):

- Sequencer (something which plays pieces of music one after the other?)

- Sampler (what on earth is the difference between Sampler and Recorder??)

- Grooves (and what are "fat" grooves??)

No matter how often I read the leaflet,I still can't understand the difference between sampling and recording...

Many thanks,

Father James Vereker