In a recent viabrevis posting (“Carved in Stone, Cast in Concrete”), we looked at messages written in (or on) stone but neglected to say what such messages are called, not so much for lack of a word as the difficulty of choosing among the various possibilities. For example, how should we refer to the rock writing in the following illustration?
Spiritual Power petroglyph

“SPIRITUAL POWER” could be called either a petroglyph or a petrograph, and the painted graffito could be called either a pictograph or pictogram. *Pictoglyph and *petrogram seem to be nonstarters, though the fuzzy semantic boundaries among the suffixes
–glyph, -graph, and –gram make them plausible runners-up.

-glyph comes from Greek γλυφή ‘a carving’ from the verb γλύφειν ‘to carve, cut out.’ (It was by scratching desert varnish from rock faces that the Anasazi and other Native Americans created the New World’s earliest petroglyphs. The 20th-century stone mason who gave us “SPIRITUAL POWER” used a similar technique.) By extension, glyph came to designate specifically ‘a written (esp. carved) symbol or ornament’ (as in hieroglyphics, sometimes now used facetiously to refer to indecipherable writing) and, more recently, simply ‘an informational symbol’ (as in the somewhat arcane autoglyph—a multidimensional pixel—or the more mundane picture identifying a men’s room):
Men's room glyph

-graph comes from Greek γραφή ‘something written’ (as in autograph ‘something written by oneself’ [αὐτός ‘(one)self’] or biography [βίοσ ‘life’] ‘a written account of a life’) whose meaning has been extended to ‘something that writes or describes’ (as in phonograph ‘device for recording and reproducing sound [φωνή ‘sound’]), from the verb γράφειν ‘to scrape, scratch’ (cognate with the –grave of engrave) and, by extension, ‘to write.’ As a specific kind of written object, γραφή could mean ‘line,’ whence graph in the sense of ‘diagram representing numerical values.’ The dual use of –graph to refer both to that which is written and that which writes that has been the source of some confusion.
-gram comes from Greek γράμμα ‘something written or engraved,’ a noun formed from the verb γράφειν. So, for example, a telegram is the “writing” produced by a telegraph. Or, more graphically, “Season’s Greetings” is the psammogram (ψάμμος ‘sand’) and the psammograph is the stick that the likely psammographer (the gentleman in the sweatshirt) is brandishing in the picture below.

Psammogram, psammograph, and psammographer
The suffixes –glyph, -graph, and -gram are Greek and, with some notable exceptions, are generally preceded by Greek combining roots—petro- (πέτρα ‘rock’), phono- (φωνή ‘sound’), psammo- (ψάμμος ‘sand’), and so on. Indeed, words consisting of a combining root and a suffix tend to be of the form Language1 + Language2 (Greek + Greek, Latin + Latin, English + English): compare, for example, manuscript (Latin manus ‘hand’ + Latin scriptus ‘written’) and English woodcut with the preceding Greek + Greek examples.

There are, of course, exceptions to this rule of thumb—for example, pictograph and typewriter, the former consisting of a Latinate root and a Greek suffix, and the latter consisting of Greek root and a native English suffix. Hybrids result from a number of factors, which include (a) the phenomena the hybrids designate were unknown to the ancient Greek- and Latin-speaking world, (b) the appropriate Greek or Latin affix is already in use and can’t be recycled without potential ambiguity (as in the case of
–graph), (c) knowledge of Greek and Latin has become less common, and people have come to think of the building blocks for new 25¢ words as residing in a single mixed bag marked “Classical Language” which can be drawn from as needed without regard to specific language of origin, (d) given the choice between a Greek, Latin, or native English affix, familiarity with one over another may tip the balance, or (e) sociolinguistic considerations favor the creation of something between an Anglo-Saxon 5¢ new word and a classical 25¢ neologism.

Pictograph and typewriter (both coined in the mid 1800s) are illustrative cases in point, one to designate something old and the other, something new. The picto- of pictograph comes from Latin pictus ‘(something) painted’ from the verb pingere ‘to adorn with colors, to paint, to tattoo.’ (The Picts are generally thought to be so called because of the practice, described in Caesar’s De Bello Gallico, of dying their faces blue, making their appearance “more horrible in battle.”) Why picto- instead of a Greek combining root? Presumably it was pingere’s extended meaning of ‘to draw (a picture)’ that the coiners of the term (and its slightly later cousin, pictogram) had in mind,’ picture being a commonly known and appropriate point of reference, and for that reason alone surely preferable to, say, *glyphograph.

The type- of typewriter is Greek in origin (τύπος ‘a blow, an impression [i.e., the mark made by a blow]’) but it’s unlikely that the person who coined the term had that in mind. Rather, it seems plausible that the idea was to present the new technology in as readily accessible, user-friendly terms as possible. (Not so friendly is the typographical error, made only slightly more friendly when shortened to typo.) In France, on the other hand, what has come to be generally called a machine à écrire (‘typing machine,’ like machine à laver ‘washing machine’) was originally dubbed a dactylographe or (as my Petit Larousse from the 1920s says is preferable) dactylotype, δάκτυλος being Greek for ‘finger,’ and while a French typist is still a dactylo (short for dactylopgaphe ‘personne dont la profession est de taper à la machine’), dactylographie in the sense of ‘typescript’ is now more commonly tapuscrit.