I am little confused with these words replication,download,moving,copying and mapping..

Hi everyone !

                    I am little confused with these words replication,download,moving,copying  and mapping in sap  CRM..

                    Can anyone explain me what objects we do copy, what objects we replicate, what objects we move and what objects we map from SAP R/3 to sap CRM  or CRM to R/3 ?

                   Please share me the documents if you have. My email id is aanchalverma07@yahoo.com..

Thanks In advance