The usual Japanese word for dollar-denominated currency; often clarified as 米ドル when specifically referring to the U.S. dollar.
from Dutch
この本は二十ドルです。
This book is twenty dollars.
空港で円をドルに両替した。
I exchanged yen for dollars at the airport.
A colloquial or slang-like extension meaning money or cash in general; お金 or 現金 is the normal everyday wording.
古い俗語では、「ドル」が現金の意味で使われることがある。
In older slang, doru may be used to mean cash.
This bag is 100 dollars.
Overseas, it's often more convenient to pay in dollars than in cash.
I exchanged yen for dollars at the bank.
The dollar has been strengthening rapidly lately.