<p>I've come across this term POD-type a few times.<br>
What does it mean? </p>

POD
stands for
Plain Old Data
- that is, a class (whether defined with the keyword
```
struct
```
or the keyword
```
class
```
) without constructors, destructors and virtual members functions.
Wikipedia's article on POD
goes into a bit more detail and defines it as:
A Plain Old Data Structure in C++ is an aggregate class that contains only PODS as members, has no user-defined destructor, no user-defined copy assignment operator, and no nonstatic members of pointer-to-member type.
Greater detail can be found in
this answer for C++98/03
. C++11 changed the rules surrounding POD, relaxing them greatly, thus
necessitating a follow-up answer here
.