According to a few sources, adapter can refer to several things:

• a fitting that connects pipes of different materials ^{[1] [2]}
• a fitting that connects pipes of different diameters or genders ^[3]
• a fitting that connects threaded and non-threaded pipe ^[4]

Since all these definitions fall under Piping and plumbing fittings, I suggest that this page redirects to the root of that page rather than § Reducers, since adapters can encompass more than just reducers.

@ Peter Horn: is there any reason to redirect specifically to § Reducers, other than that's how it's always been?

Andrew Lorimer ( talk) 04:46, 3 July 2019 (UTC) reply

I see what you are getting at. Perhaps we can add a specific section called adapters to the article listing all the items that you list along with the references you have provided. Peter Horn User talk 11:20, 3 July 2019 (UTC) reply

Alright, I've made a new section at Piping and plumbing fitting § Adapter. I'll now change this page to redirect there. Andrew Lorimer ( talk) 11:32, 4 July 2019 (UTC) reply

@ Andrew Lorimer: There is another kind of piping adapter, one that allows NPT systems to connect to BSP systems. As far as I know these are only mentioned in suppliers catalogues. More on this later. Peter Horn User talk 12:25, 7 July 2019 (UTC) reply

@ Andrew Lorimer: Just one sample ^[5] Peter Horn User talk 20:30, 7 July 2019 (UTC) reply

Valid point. Since this is a very specific function, I'm inclined to include this type of adapter under the list item for "a fitting that connects pipes of different diameters or genders or thread types". I'll do that now, but let me know if you have any objection. Andrew Lorimer ( talk) 08:18, 8 July 2019 (UTC) reply