I'm using a formula that returns an Array of strings, so the result overwrites a range of cells, but I want to get the result in just that one cell. (The actual formula I'm using is WIKISYNONYMS from a 3rd party add-on, but that shouldn't matter.)I tried using ARRAY_CONSTRAIN, eg.=ARRAY_CONSTRAIN( WIKISYNONYMS(en:Berlin), 1, 1 )But that throws away all the data that would have gone beyond the constraints, rather then constraining all the data to that one cell.So I tried using concatenate, eg.=CONCATENATE( WIKISYNONYMS(en:Berlin) )And that is close, but I need to add ,  or something like that between each entry for readability.
Constrain a Array formula result to a list in a single cell
google spreadsheets
You can use JOIN to stitch the pieces together with a given delimiter:=join(,, f o r m u l a ) 