I was going through a definition about cylinder which states that :
A cylinder is a surface generated by a variable straight line which moves parallel to a fixed line and intersects a fixed curve not lying in a plane parallel to the fixed line or touches a given surface . The given curve is called the guiding curve or directrix and the variable line is known as generator. If the guiding curve is a circle and the fixed line is normal to the plane of the circle through the centre of it, then the cylinder is right cylinder and the fixed line is called the axis of this cylinder.
This is a very lengthy definition given, (or maybe a long information but either way,) I am not getting what are they trying to mean ? Can anyone explain what are they trying to mean ? Also,what's the difference between right cylinder and a normal cylinder?I am not getting which is the guiding curve and directrix and wha's the generator ? Also, I have just started an elementary course in analytical geometry so ,I dont know much about this , so I need a "simplified" or rather an "elementary level explanation "(if that's possible at all ) ...But I am not quite getting this...