different between rollover vs turnround

English

roll +? over, from the verb phrase.

rollover (countable and uncountable, plural rollovers)

The process of incrementing, especially back to an initial value.
(automotive) A road traffic accident in which a vehicle overturns.
- 1980, Stephen King, Big Wheels: A Tale of the Laundry Game
  “They blink if I step on the brake at the same time, and anybody who don't step on his brakes when he's makin^[sic] a turn is lookin^[sic] to do a rollover.”
(computing) A graphic element that changes its appearance when the cursor moves over it.
(computing) A keyboard feature where each key is scanned independently, so that multiple simultaneous keypresses always register correctly.
(finance) The reinvestment of funds in a new issue of the same or similar investment.
(finance) A fee paid by a borrower in order to defer full repayment of a loan.
(Britain) In the National or European lottery, the situation in which a jackpot that has not been won is carried over to the next week.
(pinball) A target on the pinball table that is activated when the ball rolls over it.
- 2010, Bob LeVitus, Incredible iPhone Apps For Dummies (page 78)
  One thing I hate about some pinball games is that they don't let you know your current objective, what happens when you hit specific targets or rollovers, or what targets you should be aiming for right now.

From turn +? round

turnround (plural turnrounds)

Send