Long Answer
It's been years since I learned all of that stuff, but I think the dropped frames is called "Step Printing" - or else that's the opposite where they add frames.
Either way, for script purposes, I'd just describe what the audience is going to see without any technical terms. Here's a LONG example from the very end of the script I'm getting ready to produce:
WE ZIP BACKWARDS THROUGH TIME - everything around the Top Cat backpack a blur of motion.
EXT. THE PIER -- NIGHT
Stopping when Sandi hands Laura (in her bathing suit) the Top Cat backpack filled with her clothes. Laura pulls Sandi into her arms and kisses her - one hell of a kiss. A DRUNK in the background watches them make out.
ZIP BACKWARDS - Sandi seems to take back the backpack, she and Laura get on the boat... then everything but an oar becomes a blur of motion.
EXT. OCEAN -- NIGHT
Stopping when Sandi rows the boat to the buoy, where Laura clings for her life. Sandi helps Laura into the boat.
ZIP BACK - everything around the Top Cat backpack on Sandi's back a blur of motion.
INT. BEACH HOUSE BEDROOM -- NIGHT
Sandi sets the Top Cat backpack down next to the dresser, counts down to drawer number four and opens it.
Behind the clothes in the fourth drawer - a vial of pills. Sandi tosses the vial into the backpack with Laura's clothes.
ZIP BACK - everything around the pill vial a blur.
***
I think anyone reading that would get an idea of what I want. The best thing about doing it without the tech terms is that actors will understand it - and you need them to get the film made.
- Bill