Simple past tense and past participle of adjoin.(verb)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "adjoined" in a sentence
"Indeed, he's just had a noteworthy encounter at The View, where his dressing room adjoined that of singer Mary J. Blige, who was also a guest on the show."
"We kids would be scrubbed clean, dressed neatly, and expected to wait behind the swinging kitchen door as the guests settled in the living room which adjoined the dining area."
"I kicked my clothes to one side and stepped into the tiny bathroom that adjoined my room."