Top line --> revenues
Bottom line --> profit
Let me detour a bit to stress one thing I often see candidates screwing up during interviews.
Consulting companies and especially MBB tend to focus 99% of their cases (both in real life and during interviews) on the operative part of the P&L that is revenues and operative costs alone and they use EBITDA (and not Profit) as the main profitability measure.
So during a case interview, it is very unlikely that the path to the solution will require you to analyze depreciation, amortization, interest, or extraordinary items. If possible always stick your analyses to revenues and operative costs.