What is the meaning of Signum?

A sign, mark, or symbol.

A medieval tower bell used particularly for ringing the eight canonical hours.

A function that extracts the sign of a real number x, yielding −1 if x is negative, +1 if x is positive, or 0 if x is zero.

visible indication: sign, mark, signal

seal, signet

emblem, ensign

watchword

symptom, prognostic

miracle, miraculous work, sign

statue, figure

constellation; sign in the heavens, heavenly sign

signum (medieval tower bell used particularly for ringing the 8 canonical hours)

the cross of Jesus Christ & Christianity.

Source: wiktionary.org