Turkey meal comes round with dinners originally for four (6)
I believe the answer is:
tetrad
'four' is the definition.
(synonyms)
'turkey meal comes round with dinners originally' is the wordplay.
'turkey' becomes 'tr' (abbreviation eg in internet addresses).
'meal' becomes 'tea' (tea is a type of meal).
'comes round' means one lot of letters goes inside another.
'with' says to put letters next to each other.
'originally' suggests taking the first letters.
The first letter of 'dinners' is 'd'.
'tr' inserted inside 'tea' is 'tetra'.
'tetra'+'d'='TETRAD'
'for' is the link.
(Other definitions for tetrad that I've seen before include "quartet" , "Group or set of four" , "number of Gospel writers" .)