"Tiempo" in Spanish (mus.) is a bit ambiguous, because it may be used in the sense of "movement". But if speaking of a "vals" (waltz), it would likely refer to the third beat in the 1-2-3 of a typical waltz. Examples of beats below (in Spanish):

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Note added at 29 mins (2003-07-16 21:13:44 GMT)
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Ex.: \"La mazurka es una danza popular de origen polaco ...Presenta diversas variantes... y su ritmo en 3/4, con la acentuación característica en el segundo o tercer tiempo da lugar a cierta libertad interpretativa.\"