I'm not familiar with these. Is it an eastern thing? Crazy profile shot, too- you're obviously pretty skilled at finding the lichen-free patches (slab climbing is interesting enough w/o lichen as it is)!
A "slide" is a landslide or a rockslide, or (and especially) the scars they leave behind. The term includes both bare slabs and rubble-choked chutes. It probably is an Eastern thing - when you've bushwhacked through fir a few times, a slide starts to look tempting as an ascent route even if it's slippery or unstable.
Slides are primarily a northeast phenomenon, though I have seen avalanche chutes in the Rockies that are similar. The mountains of the northeast were stripped bare by glaciers during the last ice age, so there is not much soil, and the soil that is there is primarily duff. During dry spells, the duff can shrink and lose contact with the rock below. If a heavy rain event follows (like a hurricane), the water flows between the duff and rock, and if conditions are right, a large landslide occurs. The scar left behind is a slide.
Is this shot taken from nippletop?