... and what is it that you do?

Pity the poor academic, in full gown on a sweltering day, standing in line and waiting for the Royal motorcade to arrive.  Then, the moment to be remembered for life, The Queen (God bless her) holds out her hand and asks the perspiring lecturer ".......and what is it that you do?"

Shades of  Her Majesty's  2008 LSE question about the financial crisis?

Any advice on a sensible answer gratefully received.  After 32 years in the Higher Education arena (not counting my own first degree) I still seek a clear definition.