Synonyms for Alto (same or very similar meaning)
WordNet sense 1 (the lowest female singing voice):
contralto
WordNet sense 2 (the highest adult male singing voice):
countertenor
WordNet sense 3 (used of sounds and voices; low in pitch or frequency):
low, low-pitched
WordNet sense 4 (used of sounds and voices; high in pitch or frequency):
high, high-pitched
From the ODE community, based on WordNet
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