What is the meaning of Tunnus?

attribute, characteristic, quality, sign

affix

symbol, emblem, sign (representative symbol)

insignia (symbol or token of power, status, or office)

seal (design or insignia associated with organization or official role)

mark (indication for reference or measurement)

motto

marker

username

credentials

ident

identifier (formal name used in source code to refer to a variable, function, procedure, package, etc.)

attribute

alternative spelling of thunnus

Source: wiktionary.org