It's a inflection of the verb sing. It means intonating melodies, using the voice. In Spain, there was a measure called canatan (obviously the tilde would be missing then). It was used to measure liquids and dry or arid substances. In volume measurements it amounted to 8 blues or 16 , 133 liters and in dried, equivalent to an at sign or 12 , 5 kilograms .
