"Arbaite" is wrong. If you talk about nouns, there are two of them in German:

die Arbeit  - the work (meaning job)

das Arbeiten - (the) working (nominalisation of the verb "arbeiten", meaning the process of working)

If you talk about verbs, like Judy suggests, then "arbeiten" is the infinitive of the verb and also the present tense of "wir arbeiten" (we work), "sie arbeiten" (they work) and "Sie arbeiten" (you work; formal). Then "arbeite" could be the imperative: "Arbeite!" (Work!) or the present tense "ich arbeite" (I work).

I think you are talking about Arbeite  and Arbeiten. Arbeite is a transformance of Arbeiten, such as "Ich arbeite...","Du arbeitest...",just like "I go" and "he goes".It changes as the subject changes.Hope this can help you understand such kind of transformance.