The patron saint of a particular group of people is a saint who would protect and 'love' the group and its members. Prayers by such people are considered more likely to be answered by their patron saint. Some consider it a special devotion to God by displaying humility in asking a saint for intercession rather than expecting to be answered themselves, calling to mind Job 42:8, which implies God's favour to the virtuous.
The feast day associated with a saint is often marked by those who have the saint as patron; this is especially the case with a national patron, whose feast day may be a public holiday. In some cases the celestial patronage is not assigned to a canonized person, but to a liturgical feast and/or (often associated) aspect of God or the Virgin Mary which is held in similar reverence (though unlike a saint it cannot actually intercede with God), such as:
Certain patron saints have only a nominal relationship with the trade or group that they represent, as is the case with Saint George of England. Saint Fiacre is the patron saint of taxi drivers, supposedly because the first hansom cabs in Paris were hired outside the Hotel Saint-Fiacre and, indeed, were known as fiacres.