salad cream vs salad dressing

salad cream and salad dressing both are nouns.

Word	Noun	Adjective	Verb	Adverb
salad cream	Yes	No	No	No
salad dressing	Yes	No	No	No

As nouns, salad dressing is a hypernym of salad cream; that is, salad dressing is a word with a broader meaning than salad cream:

salad cream: a creamy salad dressing resembling mayonnaise
salad dressing: savory dressings for salads; basically of two kinds: either the thin French or vinaigrette type or the creamy mayonnaise type

Other hypernyms of salad cream include dressing.

salad cream (noun)	salad dressing (noun)
a creamy salad dressing resembling mayonnaise	savory dressings for salads; basically of two kinds: either the thin French or vinaigrette type or the creamy mayonnaise type