The structured approach, sometimes called the traditional approach, or the scope and sequence approach, is the homeschooling approach that most resembles education in institutional schools. It's called scope and sequence to emphasize the scope is the body of knowledge to be taught and the sequence--the way it is divided up, usually into grade levels. It is the "school model".
In this approach to homeschooling, the child works on each subject separately every day. All learning is planned and followed by grade level. Schooling does not get off track and everything is covered, with no worrying about learning gaps. Many homeschool programs that use the structured approach provide textbooks for each subject, along with a teacher's manual. Tests often follow each lesson, to be sure that the child is learning. Most structured homeschools have a daily schedule. Some structured homeschoolers run their programs Monday through Friday, from June through September; others run a year-round program.
Most structured homeschools enjoy the curriculum since the units and textbooks can be purchased (no need to create them). With a purchased structured curriculum the schedules, lessons, scope and sequence are planned for you. Some parents purchase a preplanned, structured curriculum so they have something to fall back on, diminishing the worries of homeschooling. Many parents that are new to home education start with this type of program.