If the word was missing from the sentence, then it could be translated as “Give us today our bread and forgive our sins…”.
Instead, with the word added, it can be translated as "Give us today the bread we need for the day and forgive our sins… ".
I guess the significance of the word is in not being greedy and asking from God only what you really need instead of what is “owed” to you?
Get away from her you bitch!