It means, depending on the resolution and settings, it will work at 60hz, or up to 76hz. For LCD's, that generally means it is a 60hz monitor, and can only do 76hz at a lower resolution while using a DVI-D cable (still won't do it with HDMI).
Ok It's a LED monitor is it the same? ASUS VE247H 24 inch LED Widescreen
An LED monitor is a LCD with LED backlighting. So its a 60hz monitor at its native resolution, with the possibility of a lower resolution (720p or lower generally), being about to hit 76hz.