### Clue: Titanic found by old Unesco or Greenpeace, possibly, in dip (9)
### Answer: HUMONGOUS 
 ### Explanation: Definition: Titanic
 [O(abbrev. for "old") + NGO(abbrev. for "non-governmental organisation", examples of which;possibly are Unesco and Greenpeace) ] **contained in**(in) HUMUS(one of the alternative spellings of "hummus", a food dip popular in the Middle East).