Another meaning, which is incorporated into Chenrezigs mantra OM MANI PADME HUM is the Perfection of Wisdom Heart Sutra.
OM MANI PADME HUM has 6 syllables, which can be interpreted as the Heart Sutra's description of emptiness:
No eye, no ear, no nose, no tongue, no body, no mind
no visual form, no sound, no smell, no taste, no object of touch, no mental objects
no visual consciousness, no auditory consciousness, no olfactory consciousness, no taste consciousness, no tactile consciousness, no mental consciousness
LCR, June 2020