Because we do not have any type of slot machine like パチスロ in the West (at least, as far as I know... I'm sure there is none of the same type in North America) this word is a purely Japanese invention. Therefore, I believe it would be best to create a new term as I have written above and then explain what it means.

For example:
Aimed Stop - aiming for a certain picture on the slot machine's reel by stopping the reel with careful timing so that the picture falls into the slot machine's betting lines.

Slot machines found in Las Vegas and other U.S. casinos do not feature any type of "aimed stop" such as this, and instead are completely controlled by the internal computer to stop at whatever point the computer decides. Jackpot reels are of course impossible to aim for, and only occur at very poor odds.