The formula 'Señora de' or 'Viuda de' is almost unused nowadays. You won't find anyone younger than 60 who call themselves that way. And, as Fernando says, it is not a legal name, simply an old fashioned way to be known.
About the colín, it is the name of a stick of bread, that can be short (about one inch, like those in Andalucia, known as picos, too) or really long (up to two feet, like those sold in Madrid, unfortunately in less and less bakeries).