Though many people use the term "ranch house" to refer to any one-story home, it's a specific style too.
The modern ranch style evolved in the post-WWII era, when land was plentiful and demand was high. On large suburban lots there was no need to conserve space by building up, so ranch home plans expanded outwards on a single story, causing them to be known as ramblers in some regions. Since living spaces are on one level, ranch house designs are often ideal for aging in place or accessible living. The style typically features a wide profile and a gable roof without excessive embellishment, often making this an affordable choice to build. Inside, layouts are casual and relaxed, and often feature an open kitchen. Outdoor living takes place on porches or patios. This style often is paired with a slab foundation, making it a common choice for places like California or the West where basements are less common. The split-level layout is a variation.