This is the mantra of Padmasambhava, 'The Lotus-Born One'. He is attributed with having brought the Dharma (Buddhism) to Tibet. These syllables can be thought of as Padmasam…bhava in sound form. There is no real translation - they don't really 'mean' anything, at least not logically speaking. But... 'Om' is supposedly the purest, most fundamental sound in the universe. It is called a 'seed syllable'. 'Ah' and 'Hum' are also seed syllables - together they can be seen as representing body, speech and mind. 'Vajra' is a key symbol in Mahayana Buddhism. It means 'diamond' and also 'thunderbolt', and relates to the unification of opposites and to overcoming (or smashing through) obstacles. 'Guru' means something like 'teacher'. And 'Vajra guru' is a synonym of Padmasambhava. 'Padma' means lotus, and is another key Buddhist symbol. 'Siddhi' means 'spiritual power' or 'spiritual attainment'. (MORE)