I am a memory made of light, captured once, then held tight. What am I?

I make blending ingredients easier, and sometimes even hands free. It's also essentially what a dj is.

A school’s paper companion, A scholar’s delight, An artist’s tool, And a banker’s nightmare.

There's a famous one in France. There's a famous one in Rome. There's a famous one if by chance, you pass the burger place by your home. What structure am I referring to?

A reference book abundant with a plethora of monosyllabic and polysyllabic linguistic forms, often with pronunciation and etymology. Start with the woman who Elton John replaced Marilyn Monroe, followed by a state that is basically a suburb of NYC. Next a type of engine used for rocket propulsion, then a very short word. Finish with an Australian singer whose last name is X.