Tahor means clean, pure, or ritually uncontaminated. It appears about 95 times. It describes ritual purity, moral purity, and the pure gold used in the tabernacle.
Purity teaches that approaching a holy God requires preparation and transformation. The clean/unclean distinction trained Israel to discern between holy and common. Jesus offered the ultimate purification — 'Blessed are the pure in heart, for they shall see God.'