Functional Organization:
An organizational structure in which staff is grouped by areas of specialization and the project manager has limited authority to assign work and apply resources.
Projectized Organization:
Group employees, collocated or not, by activities on a particular project. The project manager may have complete, or very close to complete, power over the project team.
Matrix Organization:
Any organization in which the project manager or project team leader actually shares responsibility for the project with a number of individual functional managers.