American Proprietary Eponyms
An eponym is a general term used to describe from what or whom something derived its name. Therefore, a proprietary eponym could be considered a brand name (trademark or service mark) which has fallen into general use.
We've all seen it happen. The commonplace products and services of today become the household word of tomorrow. Well, some might say ’tis the price companies pay for a popular product.
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In general, an eponym succeeds only if it can convey its purpose successfully without adjectives or modifiers. For example “Use some saran wrap” works as successfully as “Use some saran wrap to keep your food fresh.” In fact the former sentence is agreeably less redundant.
So, what leads a brand name to become an eponym? Well, for one thing, other brands of a similar nature or purpose must exist; but even more importantly, the original product, even if discontinued, must still function pronominally. In other words, a specific can be used to designate a class of generics with no loss in meaning. The usual result: lower case transcription of the brand name.
Now, here's the twist: Brand names are, in fact, neither nouns nor verbs, but the rare case of proper adjectives.
By convention, to recognize such words, a noun such as “brand” and/or a noun phrase describing the product or service is used. The brand name must also be capitalized (order of of decreasing acceptability: SARAN WRAP, SARAN WRAP, or Saran Wrap) or made distinct from the surrounding text (order of decreasing acceptability: Saran Wrap, Saran Wrap, or Saran Wrap). After the first occurence of the word in writing, however, initial caps are all that is needed.
Taking this into account, the above imperative would be ideally stated “Use some SARAN WRAP brand food storage wrap,” which not only shows respect, but precludes any misinterpretation of ownership.