Is there a word for a somewhat misguided definition?

Question

To clarify my question, a company I'm working at uses a term (ABC, for example) to describe one of their products (canned soup, for example). Based on knowledge of the term itself, there is no way you could figure out what the product is, or even how the term was originally coined, unless you had some historical knowledge. In this example, let's say that the company used to sell only alphabet soup, hence the name ABC, which stuck. Is there a term that corresponds to this definition, which is somewhat nonsensical, unless one is aware of the historical background?

My intuition is leaning towards the word, misnomer, although I feel that there may be something more fitting.

Answer 1

I understand your question to ask for a word to describe a product name that derives not from the product but from other association of the product with its origin, company or other influence.

Perhaps moniker is relevant:

Merriam Webster
informal
NAME, NICKNAME

• "Hoosier" is a common moniker for a resident of Indiana. Twentysomethings. Generation X. Slackers. Why isn't there a standard moniker for the flannel-clad, grunge-happy, jaded, cynical loafers born in the Sixties and Seventies? — James Aley
• Living up to the exclamation mark occasionally inserted into her moniker, P!nk belts loudly, raps lustily, moans orgasmically, and, unlike Britney, is altogether believable as an out-of-control party monster. — David Browne
• More than a half-dozen automakers have announced electric pickup trucks, and Ford has chosen the Mustang monicker for its new compact electric SUV. - Bill Howard

These monikers reflect real or imagined characteristics of people (Indiana residents, loafers), a person (the rap artist P!nk), and a car (Ford).

ABC is the company’s moniker for a canned soup. It reflects the company’s origin as a maker of alphabet soup.

If you need a higher register word, albeit not fitting your question so well, you might use sobriquet

Cambridge a name given to someone or something that is not their or its real or official name

Such nicknames are not necessarily “misguided”, although they may sometimes be so. Here is an example:

Listverse
Kagome has grown to become the largest producer of Japanese tomato products and a major producer of other fruit and vegetable foods. Unfortunately, in Portuguese and probably Spanish this sounds like “I shit myself”.

Answer 2

You might try:

anachronism noun
2 : a person or a thing that is chronologically out of place
      especially : one from a former age that is incongruous in the present
_{Source: Merriam-Webster — anachronism}

The name ABC was relevant back when the company had only soup with letters in it. Today, it is out of place.