Oṃ Namaḥ Śivāya (ॐ नमः शिवाय) is commonly understood as “Om; reverence or salutations to Shiva.” Namaḥ expresses homage or bowing; Śivāya means “to Shiva.” The opening Oṃ is a sacred syllable with its own interpretive history and should not be reduced to a simple English word.
For many Shaiva devotees the expression is a way of remembering Shiva and cultivating devotion, not merely a verbal greeting. The core namaḥ śivāya phrase is associated with the Śrī Rudram tradition of the Yajurveda. Schools also read symbolic meanings into the syllables, but those are tradition-specific theological interpretations, not literal translations of the Sanskrit words. Whether and how it is used in a formal practice may depend on one's community or teacher.