What is meant by intraplate volcanism? I am having massive confusion on whether intraplate volcanism refers to volcanism occurring at plate boundaries or away from plate boundaries (such as formation of ocean island basalts), or perhaps both?

Also, are mid-oceanic ridges related to intraplate volcanism?
Terms:
Intraplate volcanism - as the name suggests it is volcanism within the plates rather than at plate boundaries.

These are also known as hotspots. 

Ocean island basalt (OIB) - is the basaltic rocks associated with intraplate volcanism.  

Relation between mid-ocean ridges and hotspots:

Hotspot–ridge interaction produces a wide range of phenomena including excess crustal thickness, geochemical anomalies, off-axis
volcanic ridges, and ridge relocations or jumps.

For further study refer to this research paper.

A conceptual schematic of a ridge jump from that paper:





Image Source

DR: Dying rift
PR: Propagating rift  

There is a ridge jump towards the hotspot.  Due to the ridge jump lithosphere from plate B is transfered to plate A.