Having two operating systems available, such that either of them can be selected each time the computer is booted.(adjective)
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Use "dual-boot" in a sentence
"And I shouldn't fail to mention that I actually have a dual-boot machine, so I have my choice of windows environments."
"If you can handle a 10 screen, the Lenovo S10 comes with a 1024x600 display and a semi-decent keyboard, and you can easily add Kubuntu to dual-boot with the pre-installed XP."
"And the linux installating does'nt kick out the old windows OS, so you can "dual-boot"."