Synonyms and related words :
ID card, badge, calligram, calling card, card, check, checker, checkerboard, checkerwork, chessboard, colors in patches, countermark, countersign, crazy-work, credentials, dog tag, harlequin, identification, identification badge, identification tag, initials, inlay, insert, insertion, inset, letter of introduction, marquetry, monogram, mosaic, open sesame, parquet, parquetry, password, patchwork, plaid, press card, secret grip, serial number, shibboleth, signature, tartan, tessellation, tesserae, token, variegated pattern, visiting card, watchword