A bi-level includes two short sets of stairs and two levels. The entry is between floors. The front door opens to a landing. One short flight of stairs leads up to the top floor; another short flight of stairs leads down. The top floor tends to be full height ceilings with the living room, dining room, kitchen, bedrooms and bathrooms. The lower floor often has lower ceilings and is partially below ground. However, in many modern split-foyer homes, the lower level is at grade, which necessitates an outdoor staircase to reach the front door. These homes often have very high ceilings on the lower level to accommodate the home's HVAC ducting.
A modified bilevel home has a garage attached at the front of the bilevel, not under it. The front entry is larger with room for groups of people to enter and a closet. (This change addresses the major complaint about the cramped front entry space.) The garage entry also opens into the front entry. The modification is the addition of another level above the garage using a third short flight of steps going up from the great room area to additional bedrooms or a master bedroom with en suite.