I need information on the topic: Dynamic libraries for developing web resources

I need to make a presentation on computer science on the topic: Dynamic libraries for developing web resources.

I do not quite understand the term "dynamic libraries" in the topic: developing web resources. I understand "dynamic libraries" as libraries for OS (example: Windows - DLL), but not for web technology. I used a search to find information on this topic, but unsuccessfully. Also, I asked my teacher to give an example of such libraries, but he refused me, and said that I should find the information myself.

I ask you to help me, and give at least some information for a start.