A condensed account of a larger body. Also to take in and break down — both reduce something to what can be used.
Latin digestus, past participle of digerere, di- (apart) plus gerere (to carry, bear); to separate and distribute, later to break down for use.
A condensed account standing in for a larger body, or the taking-in that breaks a larger body down into what can be used. Both senses reduce something so it can be carried more easily.