| From my personal experience, strumming usually implies hitting a series of strings in one fluid motion. They're hit "at the same time." Plucking implies hitting the strings individual of each other. Example: hitting an open G, then after the G hitting fretted C on the A string. Guitar players usually strum (chords), while bass players tend to pluck more, though both players can and do sometimes use both techniques.
I think this should be in the Technique forum. | 
Strum or Pluck? 
