The concentration of the 'crystals' or T.H.C. glands from the Cannabis plant into a dry powder(usually golden or blonde in color). This can be used as the beginning steps of making 'hash', smoked individually, or added to the ground Cannabis flower itself to increase the potency of the serving. Not a noun describing the the THC, or resin itself while still part of the flowers and or plant, but rather after the act of separating the THC glands from the plant through dry and solvent-less extraction.. the resulting product is Keif.
"dang, your grinder collected a ton of keif"
"these nugs were full of keif"
"I once smoked a hit with hash ball on top, with so much sprinkled on keif that u couldn't see the bud or the hash anymore... knocked me the fuck out"