אֲדֻמִּיםʼĂdummîym

proper name [of a location]: see מַעֲלֶה below עלה

Pronunciation: ad-oom-meem' · Hebrew/Aramaic (Old Testament) · H131

Same root

אָדָםʼÂdâm · H121Adam the name of the first man, also of a place in Palestine

Where it appears

Appears 2 times in the Bible.

Joshua 15:7 From that point it went through the valley of Achor to Debir, turning north toward Gilgal, which is across from the slopes of Adummim on the south side of the valley. From there the boundary extended to the springs at En-shemesh and on to En-rogel.
Joshua 18:17 From En-rogel the boundary proceeded in a northerly direction and came to En-shemesh and on to Geliloth (which is across from the slopes of Adummim). Then it went down to the Stone of Bohan. (Bohan was Reuben’s son.)

Source: Brown, Driver and Briggs, Hebrew and English Lexicon of the Old Testament (1906), public domain; markup by unfoldingWord, CC BY (github.com/unfoldingWord/Brown-Driver-Briggs-Enhanced).