Cigar shapes split into two broad families: parejos and figurados. A parejo is a straight-sided cigar with a cylindrical body and a rounded head; the Robusto, Toro, Churchill, and Corona are all parejos. A figurado is any cigar that departs from the straight-sided shape: the Torpedo (tapered head only), the Belicoso (tapered head with a slightly fuller body), the Pyramid (more pronounced taper), the Perfecto (taper at both ends with a bulge in the middle), and the Diadema (a long, double-tapered figurado of imposing size).
Most premium cigars sold today are parejos. Figurados are harder to roll well and require more skilled blenders. A poorly constructed figurado will burn unevenly because the changing diameter changes the burn rate; a well-constructed figurado can be one of the most expressive cigars on offer.
The historical balance was different. Cuban manufacturers in the nineteenth century rolled figurados as the default; parejos were the simplification that came with industrial production. Some modern boutique manufacturers have returned to figurados as a deliberate gesture toward the older craft.
For more on cigar shapes and construction, see The Anatomy of a Cigar.