The tags [custom-application] and [third-party-software] currently have similar descriptions. Based on this the tags should be merged.
[custom-application]:
A third party application that works in tandem with SharePoint to accomplish a specific task.
[third-party-software]:
Third party software are additions to SharePoint that are sold by some other company than Microsoft. Tag questions with this when it's possible the problem or solution is related to the customization installed by the third party software.
I understand there's a slight difference between the meanings, as one points to applications and other to software. Therefore maybe just the descriptions could be extended to distinguish the tags?