/ˈnʌl.ə.baɪ/
noun · etym: null- (none) + -abye (a lullaby for nothing) · attested in marginal scholia
a quiet that follows the failure of an expected sound.
the refrigerator should have hummed. it did not. the bell of the church on the next hour should have struck. it did not. the door at five-twenty should have opened. it did not. in each of these the room becomes briefly more vivid; a small silence takes the shape of the missing thing.
nullabye is louder than ordinary silence. one's attention sharpens to fill it. compositions of nullabye have been catalogued in the catalogue as lacunary rests, though the term is contested by readers of the palimpsest.
in a sentence: "the clock had stopped during the night. i woke into the nullabye of it, and did not know the hour."