According to the tag description, the orientation is:
For question[sic] regarding the notion of orientation both in topology and in global analysis.
There is no further information in the tag wiki. A quick perusal of the first page of questions tagged with orientation (of which there are only 214) indicates that a fairly nontrivial percentage of them are not related to the orientation of manifolds or global analysis. For example:
- Questions about the orientation of the boundary in Stoke's theorem: e.g. , , 
- Questions about the orientation of vectors and othe related questions: e.g. , , , 
- A question about graph theory
Since the tag lacks a decent description and seems likely to cause confusion rather than lend clarity, I would like to propose that this tag be gotten rid of. If it has any use, it is perhaps as a synonym of manifolds.