Kush means HINDU KUSH. which is a mountain range in afghanistan pakistan and india. true KUSH is a landrace INDICA from that region of the world. how ever the term kush is abused in todays culture especially in the ghetto where "kush" usually means a type of really good bud, just like people say corns, or chronic. Kush can also refer to any type of OG KUSH mix which is a hybrid from a strain called Chemdawg, which is used to mother both the famous Sour Diesel and the Og Kush. Og kush is not the same as a Landrace Hindu Kush. Master Kush is a Hindu-kush landrace mixed with a skunk #1, and is very popular. Bubba Kush can mean two things either the Bubble gum x kush hybrid, or the pre-98 Bubba Kush strain which is completely different and more of a pure indica, not mixed with any bubble gum. sometimes the term gets confused into other regoins indicas... for example burmese kush, or nepalese kush. those are indicas, just not from the hindu kush region. ALSO there are kush landraces that dont go by the KUSH name such as Chitral. Chitral is a village atop the summit of the hindu kush mountains, hence the name for the strain. Also many pakistani, and Afghani indicas are hindu kush strains. many other pure landrace indicas come from that region of asia, such as taskenti(uzbekistan) Mazar(afghanistan) Kashmir(india/pakistan) Malana (india) Iranian-indicas(eastern Iran) Crimea/Ukranian(south-eastern Ukraine) Yunnan/Chinese-indicas(far south-western China, bordering india and pakistan). As you head east or south from those regions you will see that the genetics become much more sativa quickly. indicas come mainly from harsh mountain climates in high altitudes, where as sativas are from warmer, more tropical regions. for example Nepal is famous for strong hardy indicas, and highly psycho-active sativas. India has widely familar indicas such as the father of white widow(probably malana), and part of Barney's Vanilla kush is from Kashmir, so is their Nightshade. However in southern India where the elevation is much lower and its much hotter they have the big lanky energetic sativas.
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So basically nowadays "kush" can mean a lot of different things. typically here in Flint Michigan it means O.G. Kush, or if someone wants to add some hype to a bag of good greens they will call it kush... even if its not and they know it. The real meaning of it is the Landrace Hindu Kush indica, so keep that in mind! hope i helped!