1. Form into group: to bring people or things together, or come together, to form a group 
2.   Harvest something: to pick or harvest a crop 

  There are lots of meanings for todays key word . I think these two are the most appropriate for todays verses>

 Here there are two additional angels , one with a sharp sickle and another who had power over fire . They are preparing to harvest the grapes for they are fully ripe >

 The reference to grapes and the vine here is simply referring to the people left here on earth in this final 7 years of time . The Lord refers to the Vine and the harvest all through the Bible . Symbolically , these terms are used many times in Gods word , both in the old and the new testimont >