Mythical giant (4)
'mythical giant' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for titan that I've seen before include "One of the mythological Greek giants who ruled the world" , "Giant -- rocket" , "Taint (anag.)" , "distant moon" , "Saturn's largest satellite" .)
(Other definitions for ogre that I've seen before include "Monster, troll" , "character in 'Puss in Boots'" , "Man-eating monster of fairy tales" , "Wicked giant" , "Wicked and inhuman person" .)