the act of sustaining life by food or providing a means of subsistence; "they were in want of sustenance"; "fishing was their main sustainment"
The upkeep of a group of people or services is the process of providing them with the things that they need. He offered to pay £100 a month towards his son's upkeep. = maintenance
activity involved in maintaining something in good working order; "he wrote the manual on car care"
The upkeep of a building or place is the work of keeping it in good condition. The money will be used for the estate's upkeep The maintenance department is responsible for the general upkeep of the park. = maintenance