Canonize in this context refers to a religious ceremony performed by a high church authority. A bishop cannot canonize a saint; only the pope has that authority.
Pro Tip 2/3
Not Universal
Not all Christian denominations canonize saints, primarily a Roman Catholic practice. Protestant churches do not canonize individuals like the Catholic Church does.
Pro Tip 3/3
Historical Impact
Canonized saints often have historical significance and are honored on specific feast days. Saint Patrick, canonized long ago, is celebrated by many on March 17th.