1. Grouped together.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• clusted,
• cluddered,
• clusterd,
• cludered,
• cluttereed,
• clusteres,
• clutered,
• cultered,
• flustured,
• glistered,
• clostered,
• cluastered,
• clusteed,
• clustreed,
• clustured,
• clustared,
• clasperede,
• Custred,
• closuered,
• illsterred

• closed book,
• claystone,
• closed shop,
• close down,
• cluster bean,
• closed-door,
• claustrum,
• closet auger,
• clustering,
• closed in,
• cluster bomb,
• flustered,
• closet,
• cloister,
• closed,
• Clattered,
• closed-ring,
• cluster,
• Blustered,
• closedown,
• clyster,
• closed loop,
• cloistered,
• cloistral,
• cluttered.

The adjective form of the word "clustered" is "clustering".

The plural form of the word "clustered" is "clusters"

The singular form of the word "clustered" is "cluster"