Dir is a tribal family similar to Darood.
You have tribal families like:
Dir
Darood
Isaaq (some consider Isaaq to be of full Dir affiliation)
Hawiye
Rahanweyn
Dir are dispersed throughout the Somali peninsula and are considered to be one of the biggest Somali clans.
Dir subclans include Ciise, Gadabuursi, Isaaq (some argue otherwise), Gurgura, Magaadle as the Northern Dir.
Then you have Surre, Biyomal, Gaadsan, Garre and others as the Southern and Central Dir.
Dir are a majority in Djibouti, Somaliland (if you include Isaaq). They live in huge numbers in both Ethiopia and Kenya too.