Disclaimer: I am not an Authority on Heraldy, just read up on it alot.
Lynda Crackett is partially correct, as when CoA is mentioned, we mostly think, by default, of the region of Greater Britannia. CoA's in that sphere are issued to an individual, not a family, and registered with the issuing authority, e.g., Lord Lyon King of Arms (Scotland), or the College of Arms (UK), at least as far as the British Isles and Ireland are concerned. It has been common practice outside of an issuing bodies jurisdiction (i.e., 'Murica), for profiteers to sell "Family" coat of arms, based on a common visual interpretation of a commonly known Blazon for a given Surname. We have all fallen into this "my family coat of arms" at some point, and only after actually reading, and learning what a CoA is, as it pertains to differing parts of Europe and it's socio-political classes, do we understand that a Family Crest, Family CoA or other pretty Baubles hawked at your local Ren-Faire or on Zazzle, are just that, baubles. Cool? yes. Pretty? yes. Accurate? debatable. Can you posses imagery of it? Of Course (some restrictions apply in regions under an issuing Authorities control).
Now Rita Deniston, given your request for a Germanic name (Hoss), they handle CoA differently. A quick Google turns up a couple interpretations, as well as some sources on how German and Nordic Countries handle, issue and govern Arms. Harrison would fall under the UK system, and not "family" owned.
Me personally, I recommend people read up on CoA's first (start here: https://en.wikipedia.org/wiki/Coat_of_arms),
then locate the Blazon (Written description) and then find or even create your own interpretation.