One Latin translation contains island origin (7)
I believe the answer is:
initial
'origin' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'one latin translation contains island' is the wordplay.
'one' becomes 'i' (Roman numeral).
'translation' is an anagram indicator.
'contains' means one lot of letters goes inside another.
'island' becomes 'i' (geographical abbreviation).
'latin' is an anagram of 'nital'.
'nital' going around 'i' is 'nitial'.
'i'+'nitial'='INITIAL'
Can you help me to learn more?
(Other definitions for initial that I've seen before include "Start of name" , "Introductory" , "First - opening" , "Let; rent" , "Relating to the beginning" .)