Engineered Hardwood Flooring is constructed with a ply wood core or substrate with the actual wood on top called a ware layer or veneer. Solid hardwood is the actual wood all the way through constructed to be installed. With engineered flooring the design is to add stability and a moisture barrier to help the floor perform on the sub floor. The reason that engineered is better for wide plank options is because of the extra stability. Solid hardwood flooring is much more sensitive to moisture, so you want to get away from being stuck on solid. Not to say that solid can’t be installed in a home, but there is more risk when installing a solid hardwood floor.