1. cardinal
2. central, fundamental, primal, important, of import, operative

1. significant, important, device
2. explanation
3. pitch
4. tonality
5. musical notation, kilogram
6. kg, kilo, samara
7. key fruit, achene, Key
8. Francis Scott Key, lawyer, attorney, poet, cay
9. Florida keys, coral reef, paint
10. space, list
11. listing, list
12. listing, positive identification
13. winder
14. mechanical device, keystone
15. headstone, building block, lever

1. identify
2. discover, key out, distinguish, describe, name, supply
3. provide, render, furnish, vandalize
4. vandalise, harmonize
5. harmonise, chord, harmonize
5. harmonise, reconcile