Q: What does it mean that the filing date is in 2014 and the date of patent is in 2018? (E.g. “effective filing date?”)

A: The date of the patent is the date at which the patent starts to be enforceable. This is called the "issue date" or "grant date".

The day that you apply for a patent is the "filing date". It takes many months or years from the filing date to the issue date. If a patent issues in 2018, then it is reasonable that it was filed in 2014.

If there is some sort of a continuation of an earlier patent application (a CIP, or divisional, or a continuation, or a national phase of a PCT, etc.), then for many purposes the rights in the continuation go back to the filing date of the earlier application, and not the actual filing date of the continuation. This filing date of the earlier application is called the "effective filing date" of the continuation.

A: To augment the fine answer by Mr. Mlynek, it is worth noting that an application can also claim the benefit of an earlier filed provisional application. This differs slightly from claiming priority to an earlier non-provisional application in that you get the possible benefit of the earlier application giving your pending claims an earlier date to filter what is relevant prior art BUT you do not start the 20 year clock for calculating the term of the patent. Thus, even without modifications from patent term adjustment (PTA) or patent term extension (PTE), the term of your patent can be extended out to 20 years from when the earliest non-provisional application was filed which may mean 21 years from the filing date of the first provisional application.

I hope this helps.

Kevin E Flynn