initials (?.)

• ID card
• John Hancock
• X
• autograph
• badge
• calligram
• calling card
• card
• christcross
• cipher
• countermark
• countersign
• countersignature
• counterstamp
• credentials
• cross
• device
• dog tag
• endorsement
• hand
• identification
• identification badge
• identification tag
• letter of introduction
• mark
• mark of signature
• monogram
• press card
• seal
• serial number
• sigil
• sign manual
• signature
• signet
• subscription
• tessera
• visa
• vise
• visiting card