sum (n.) 1
summary, gist, essence
2H4 I.i.131 [Morton to Northumberland] The sum of all / Is that the King hath won
AC I.i.18 [Antony to Messenger, of the news] The sum [i.e. tell it briefly]
Per III.Chorus.33 [Gower alone, of the news that Pericles is a king] The sum of this ... / Y-ravished the regions round