The Passionist 'Sign' consists of a heart shape, the symbol of Love, surmounted by a white Cross.
It is a reminder of the Suffering Love shown by Jesus for us on the Cross.

The words in the heart are:

JESU - Name of Jesus in Latin
XPI - Short form of Christ in Greek
PASSIO - Word 'Passion' in Latin.

The text reads :-
The Passion of Jesus Christ.

Underneath the lettering are three nails - representing the nails used to fix Christ to the Cross.