The Liturgy of Funeral Offerings: Chapter III: Description of the Offerings: The Tenth Ceremony

The SEM priest next brought in a vessel four balls, or round cakes, called shaku, and whilst he presented these the Kher heb said:--

The Sem priest presenting shaku.

O Unas, the SHAKU Of Osiris have been presented unto thee, the SHAKU from the top of the breast of Horus, of his body hast thou taken to thy mouth."

The exact meaning of the word shaku is unknown, but it seems clear that the object symbolized the nipples on the breast of Horus, or the nipples on the breast of his mother Isis, which the god had taken into his mouth.