The origin of the word ''Khartoum'' is uncertain. One theory argues that it is derived from Arabic  (, "trunk" or "hose"), probably referring to the narrow strip of land extending between the Blue and White Niles. Dinka scholars argue that the name derives from the Dinka words  (Dinka-Bor dialect) or ''khier-tuom'' (as is the pronunciation in various Dinka Dialects), translating to "place where rivers meet". This is supported by historical accounts which place the Dinka homeland in central Sudan (around present-day Khartoum) as recently as the 13th-17th centuries A.D. Captain J.A. Grant, who reached Khartoum in 1863 with Captain Speke's expedition, thought the name was most probably from the Arabic  (, "safflower", i.e., ''Carthamus tinctorius''), which was cultivated extensively in Egypt for its oil to be used as fuel. Some scholars speculate that the word derives from the Nubian word  ("the abode of Atum"), the Nubian and Egyptian god of creation. Other Beja scholars suggest ''Khartoum'' is derived from the Beja word , "meeting". Sociologist Vincent J. Donovan notes that in the Nilotic Maa language of the Maasai people,  means "we have acquired" and that the geographical location of Khartoum is where Maasai oral tradition claims that the ancestors of the Maasai first acquired cattle.