tessera (n.)

• badge
• card
• check
• checker
• checkerboard
• chessboard
• countersign
• credentials
• harlequin
• identification
• inlay
• insert
• insertion
• inset
• marquetry
• monogram
• mosaic
• parquet
• parquetry
• password
• patchwork
• plaid
• shibboleth
• signature
• tartan
• tessellation
• token
• watchword