See the entire entry for zmār, zmārā v.n. song

Dan3:7 :בֵּהּ־זִמְנָא כְּדִי שָמְעִין כָּל־עַמְמַיָּא קָל קַרְנָא : at that moment, while all the people were hearing the sound of the horn

See the entire entry for kaḏ conj. when