Smith's Bible Dictionary (1863)
(palm grove). (Genesis 10:27; 1 Chronicles 1:21) a son of Joktan, whose settlements, in common with those of the other sons of Joktan, must be looked for in Arabia. It is thought that Diklah is a part of Arabia containing many palm trees.
Hastings' Dictionary of the Bible (1898) & Schaff's Bible Dictionary
DIK'LAH (palm tree), a son of Joktan, Gen 10:27; 1 Chr 1:21, who settled a district in Arabia abounding in palm trees; probably Yemen, in southern Arabia.
Hitchcock's Bible Names (1869)
Dildah, his diminishing