My Cambridge Essential Business Management book says a divisions are (no mention of divisional model specifically):
Organisational departments or divisions
Divisions are a key component of any organisational structure. Organisations
group workers together according to any of the following
classifications:
• Function—departments are based on the function performed. Most
organisations, for instance, group employees into one of marketing,
operations, finance, and human resources departments.
• Geographic—departments are often created based on the location
of the employees. For example, an organisation may have state or
regional branches; a transnational business will have branches
based in different countries.
• Product-based division are based on the actual product produced by
that group of employees. A sporting goods manufacturer may, for
instance, have departments such as ‘Footwear’, ‘Clothing’, and
specific types of sports such as ‘AFL’, ‘Football’, ‘Tennis’, ‘Netball’.
• Customer-based divisions are those based on a type of customer
who has special requirements. For example, a car manufacturer
will have distinct retail and fleet sales departments.