On which adult initially and a kid go cheaply abroad? (7,7)
I believe the answer is:
package holiday
'on' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'adult initially and a kid go cheaply abroad?' is the wordplay.
'adult' becomes 'a' (abbreviation).
'initially' says to take the initial letters.
'abroad?' indicates an anagram (I've seen 'abroad' mean this).
The initial letter of 'and' is 'a'.
'a'+'a'+'kid'+'go'+'cheaply'='aakidgocheaply'
'aakidgocheaply' with letters rearranged gives 'PACKAGE HOLIDAY'.
'which' acts as a link.
(Other definitions for package holiday that I've seen before include "All-in vacation" , "prearranged break" .)