Emblem
is a picture with a hidden meaning; the meaning is “cast into” or “inserted in” the visible device. Thus, a balance is an emblem of justice, white of purity, a sceptre of sovereignty. (Greek, en-ballo, which gives the Greek emblēma.) (See Apostles, Patron Saints.)
A chalice. The eucharist.
The circle inscribed in an equilateral triangle. To denote the co-equality and co-eternity of the Trinity.
A phœnix. The resurrection.