Other nonce coinages continue to arise. The terms themselves are occasionally referred to as "RAP phrases" ("Redundant Acronym Phrases phrases"). Some examples of RAP phrases include "ATM machine" (Automated Teller Machine machine), "HIV virus" (Human Immunodeficiency Virus virus), PIN number (Personal Identification Number number), "ISBN number" (International Standard Book Number number"), and UPC code (Uniform Product Code code).
Some occurrences are in the interest of another form of clarity: disambiguation (whereas the clarity discussed above was of a 'decryptifying' type). For example, when discussing a mainframe computer's requirements, the initialism "AC" might refer to air conditioning or alternating current depending on the context; the redundant phrase "AC current" is used by some to distinguish them, although the phrase "alternating current" is clear, correct, and not redundant. Also, the phrase "AC current" distinguishes from "AC voltage". The phrase "CSS style sheets" (Cascading Style Sheets style sheets) can also reduce ambiguity, where in certain contexts CSS could also refer to the content-scrambling system used on DVD video titles, or more commonly (as they both occur in discussion of client side web-development) cross-site scripting.
In the United Kingdom, most companies have their electrical appliances regularly checked for safety. This process is known as Portable Appliance Testing. However, it is almost universally abbreviated to "PAT testing". Presumably this is to avoid confusion with PA testing, or simply because it sounds a little ambiguous to say that one's occupation is "PAT". Sometimes similar phrases are not actually redundant; for example, a "redundant RAID" may in fact be a backup RAID in the system being described.
Acronyms and initialisms from foreign languages are also often analyzed as un-expandable nouns when they are not translated. For example, in French, "le protocole IP" (the IP protocol) is often used, and "HIV" is usually said either "le VIH" (in French, adjectives usually come after nouns) or "le virus VIH".
Another justification is that many acronyms and initialisms are trademarks, and trademark law generally treats trademarks as adjectives, which should be used with a generic noun. Examples of correct usage include "AIB Bank" (Allied Irish Banks banks), "CNN network" (Cable News Network network), and DC Comics (Detective Comics comics).
Some speakers would prefer that the expansion of the acronym/initialism be used in situations where disambiguation or clarity is needed: "cascading style sheets" instead of "CSS style sheets", "alternating current" instead of "AC current", etc. However, some people may be more familiar with the acronym than the expansion, leading to potential for confusion.