Namaste is a greeting/saying in hindi which has been translated in various ways. The most common understanding of its meaning is:
"The Spirit within me salutes the Spirit in you" - a knowing that we are all made from the same One Divine Consciousness.
Another variation is simply an honorable greeting: "The spirit in me honors the spirit in you." or "My spirit honors yours".
One of my favorite translations is slightly more lengthy:
"I honor the place in you where the entire universe resides,
I honor the place in you where the ENTIRE universe resides,
I honor the place in you of light, of love, of truth, of peace,
I honor the place in you where if you and I are in that place
then there is only one of us..."