structural:reformatting, linguistic:voice_change, information:filtering
Idiomatic use

Various ancient bilingual or even trilingual epigraphical documents have sometimes been described as "Rosetta stones", as they permitted the decipherment of ancient written scripts. For example, the bilingual Greek - Brahmi coins of the Greco-Bactrian king Agathocles have been described as "little Rosetta stones", allowing Christian Lassen 's initial progress towards deciphering the Brahmi script, thus unlocking ancient Indian epigraphy. The Behistun inscription has also been compared to the Rosetta stone, as it links the translations of three ancient Middle-Eastern languages: Old Persian, Elamite, and Akkadian.

The term Rosetta stone has been also used idiomatically to denote the first crucial key in the process of decryption of encoded information, especially when a small but representative sample is recognised as the clue to understanding a larger whole. According to the Oxford English Dictionary, the first figurative use of the term appeared in the 1902 edition of the Encyclopædia Britannica relating to an entry on the chemical analysis of glucose. Another use of the phrase is found in H. G. Wells 's 1933 novel The Shape of Things to Come, where the protagonist finds a manuscript written in shorthand that provides a key to understanding additional scattered material that is sketched out in both longhand and on typewriter.

Since then, the term has been widely used in other contexts. For example, Nobel laureate Theodor W. Hänsch in a 1979 Scientific American article on spectroscopy wrote that "the spectrum of the hydrogen atoms has proven to be the Rosetta Stone of modern physics: once this pattern of lines had been deciphered much else could also be understood". Fully understanding the key set of genes to the human leucocyte antigen has been described as "the Rosetta Stone of immunology". The flowering plant Arabidopsis thaliana has been called the "Rosetta Stone of flowering time". A gamma-ray burst (GRB) found in conjunction with a supernova has been called a Rosetta Stone for understanding the origin of GRBs. The technique of Doppler echocardiography has been called a Rosetta Stone for clinicians trying to understand the complex process by which the left ventricle of the human heart can be filled during various forms of diastolic dysfunction. The European Space Agency 's Rosetta spacecraft, launched to study the comet 67P/Churyumov–Gerasimenko in the hope that determining its composition will advance understanding of the origins of the Solar System.

The name is used for various forms of translation software and services. " Rosetta Stone " is a brand of language-learning software published by Rosetta Stone Inc., who are headquartered in Arlington County, US. Additionally, "Rosetta", developed and maintained by Canonical (the Ubuntu Linux company) as part of the Launchpad project, is an online language translation tool to help with localisation of software. One program, billed as a "lightweight dynamic translator" that enables applications compiled for PowerPC processors to run on x86 processor Apple Inc. systems, is named " Rosetta ". The Rosetta@home endeavour is a distributed computing project for predicting protein structures from amino acid sequences (i.e. translating sequence into structure). The Rosetta Project brings language specialists and native speakers together to develop a meaningful survey and near-permanent archive of 1,500 languages, in physical and digital form, with the intent of it remaining useful from AD 2000 to 12,000.