The term CALL TO can be broken down into two crossword solutions: NEXT and HAIL. NEXT is a 4-letter word that means 'immediately following in time, order, or sequence'. It can also mean 'the near future'. HAIL is a 4-letter word that means 'to greet or acclaim enthusiastically'. It can also mean 'to salute or honor someone'. Together, the two words form the phrase 'call to', which is an invitation or summons to come together.