In zoology|lang=en terms the difference between pectinid and pectiniid
is that pectinid is (zoology) any member of the pectinidae while pectiniid is (zoology) any member of the pectiniidae.
As nouns the difference between pectinid and pectiniid
is that pectinid is (zoology) any member of the pectinidae while pectiniid is (zoology) any member of the pectiniidae.