The word would be "phones" -- distinct units of sound regardless of meaning. The next level up would be "phonemes", which must contrast against other phonemes

The word would be "phones" -- distinct units of sound regardless of meaning. The next level up would be "phonemes", which must contrast against other phonemes within a particular language. For instance, in English /b/ and /v/ are phonemes, because "bat" and "vat" are two different words with only that portion changing. (This is known as a minimal pair.) However, in Spanish, /b/ and /β/ are not separate phonemes; they are two phones in complementary distribution.