from The Century Dictionary.
- noun A surplus.
from the GNU version of the Collaborative International Dictionary of English.
- noun obsolete A sum or quantity over; surplus.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun obsolete A
sumor quantity over; surplus.
from Wiktionary, Creative Commons Attribution/Share-Alike License
over- + sum
The algorithm was originally written for fetching exact sum only, but has been widened to get closest of undersum or oversum, if exact sum is not found.