Name an example of professional development in a teaching career?

please give an example of “professional development” and explain its specific importance/purpose.

Professional Development for teachers means taking classes that usually must be pre-approved by your district. Some that I’ve taken (more famous ones that you can look up online): New Jersey Writing Project and Loose in the Lab. Most of the ones that I take are presented by the district (usually your district will have a calendar of free classes for which you can sign up). I took 6 computer courses this summer, for example. If you have to administer the state test, then you know how important it is that your students pass. Many classes that you take will be directly related to increasing student performance.
These classes are important to keep you abreast of the latest theories and trends in education. They certainly help you keep up with the latest "buzzwords" which change at the speed of light. You need to know these things because they sweep through your district and you’re expected to not only know what they mean, but be able to implement these ideas as required. For example, we used to have a "GIST" process for getting students tested for special education. This year, they are changing not only the process, but it is now being called the "RTI" process instead of "GIST".