The number of grazing animals, especially cows or sheep, that can be sustained on an area of pasture. Also in "a soum of sheep": a definite quantity of sheep, defined as the number that can be sustained on a certain amount of pasture, and varying in different places from four to ten. Now chiefly historical.

The amount of grazing land which will sustain one cow (and sometimes also her most recent calf or calves), or a proportional number of sheep or other grazing animals. Now chiefly historical.

a particular amount of money

they could not afford such a sum

the total amount resulting from the addition of two or more numbers, amounts, or items

the sum of two prime numbers

an arithmetical problem, especially at an elementary level

we did sums at school, Mummy

do your sums, then the shock will not be too great

find the sum of (two or more amounts)

if we sum these equations we obtain X