What is the difference between ingot, bloom, slab, and billet?

Semi-finished casting products are classified into following types

Ingots are very large casting products, greater in size and shape than blooms, billets and slabs. Ingot generally has rectangular/square cross section, but it is not necessary that it should be uniform through out its length. (Ingot may have variable cross section.)
blooms has rectangular /square cross section.
The cross section area gof bloom is always greater than 36 in 2 (230 cm 2)
Blooms are used as rolling material in the manufacturing process of rails , seamless pipes, etc.
Billet is also a casting product. In new era of industry, generally the billets are made with the help of machine called as CCM (continuous casting machine).
Billet has a square cross section area , but cross section area of billet should be same throught its length. The cross section area if billet is always less than 36 in2. The Billets are used in the manufacturing process of Steel Rebars.
A slab has rectangular cross section, slab has thickness lesser than bloom.
If we compare Ingot, Bloom, Billet and Slab based on their weight Then Weight of ingot is greater than weight bloom is greater than Weight of billet is greater than weight of slab.