Various kinds of buffers have different names that more or less describe the functionality that they achieve such as the FIFO, or the circular buffer. They are both buffers, and serve similar purposes however their implementations are different.
I have a kind of buffer that only holds the last X seconds worth of data. So at any time when I read it I can expect the data to be within the last X seconds. Any data that is older than X is constantly dropped. Is there already a name for this kind of buffer?