Direct band gap means in E-K diagram valance bands are exactly below covalance band,in this band electon fall's c.b to v.b direct without going to metastable state
Yes it is.
Silicon is by all means an indirect band gap material.
what is indirect band gap semiconductor?
Yes it is. Most Sn (tin) materials as semiconductors are direct band gap materials. Silicon on the other hand is an indirect band gap material.