Aor SA is someone undertaking an internship within a bank, usually for 3 months over the summer after the junior year. A typically does work similar to that of a full time analyst, although with a lot more 'grunt' work (i.e. fetching coffee, moving documents between departments etc.).
The main way for graduates to get work in anis through having completed an internship as a with the bank, and then being made an offer to return full time when they have completed university.
Summer analysts have to work the same hours as normal analysts (80-100 hours a week) and are paid the same amount on a pro-rata rate (~$70k per year) but with no bonus.