The St. Xavier Library has many detailed print books
on heraldry.
This is just 1 of the excellent titles
The Heraldic imagination
929.6 D412
Gale Virtual Reference Library
multiple returns on Heraldry and Heraldic Symbolism
such as the article from The New Catholic Encyclopedia.
by Zachary Tirrell (Flickr via Creative Commons licensing)
Coat of Arms are also known as Family Crests
Conlon Coat of Arms
in honor of the amazing Julie Conlon
Search for YOUR family's crest and the symbolism behind it
Irish Heraldic Charges