Beveled edge planks have a very distinctive, deep v-groove. They lend themselves more to an informal. The deep beveling helps hide sub floor irregularities that could result in variation in height between planks.
Beveled Edge
Eased Edge Planks
Each plank has a slight beveled edge, or shallow v-groove. Eased edge is also referred to micro-beveled.
Square Edge Planks
The edges of all planks meet squarely creating a smooth, uniform surface that blends the wood floor.