Henry has two islands and part of another (5)
I believe the answer is:
haiti
'part of another' is the definition.
I can't judge whether this defines the answer.
'henry has two islands' is the wordplay.
'two islands' means two substitutions for 'island'.
'henry' becomes 'H' (symbol for the unit of electrical inductance).
'has' means one lot of letters go next to another.
'island' becomes 'ait' (term for a small island).
'island' becomes 'i'.
'h'+'ait'+'i'='HAITI'
'and' is the link.
(Other definitions for haiti that I've seen before include "Island of West Indies" , "West Indian republic" , "Country in W Indies, capital Port-au-Prince" , "West Indies republic" , "West Indies country associated with voodoo" .)