pentad /penˈtad/

1. A set of five things
2. A period of five years or five days
3. An atom, element or radical with a combining power of five

• grey-coat
• grey-coated
• grey-coats
• grey economy
• greyed
• grey eminence
• greyer
• greyest
• grey-eyed
• grey-fish
• grey-fishes
• Grey Friar
• Grey Friars
• grey geese
• grey goose
• grey-goose quill
• grey-goose quills
• grey-goose shaft
• grey-goose shafts
• grey-goose wing
• grey-goose wings
• grey-haired
• grey-headed
• greyhen
• greyhens