The word “stick” is one of those short Germanic words that form the core of the English vocabulary. Relatives of the word “stick” can be found in many Germanic languages; it can be traced all the way back to Proto-Indo-European, and it shows up in Greek and Latin. The Proto-Indo-European root is “*steig-” (the asterisk means that the form is reconstructed, as all Proto-Indo-European roots are), and according to Calvert Watkins (in the American Heritage Dictionary of Indo-European Roots) this root form meant either “to stick” as a verb or “pointed” as an adjective; we can assume, I think, that the adjective could also act in a noun formation to mean “a pointed object”.
Many of the short and common words in English have developed complex networks of meanings—long and less common words often have simpler semantic ranges. The basic sense of the English noun “stick” is something like “a long or relatively thin piece of wood”; a stick can be natural (such as a thin branch of a tree or shrub) or a shaped object (such as a walking stick or a conductor’s baton). The Oxford English Dictionary lists many other related meanings, all easily derived from the basic sense.
The OED entry for the verb forms is more complicated. The basic sense of the verb is something like “to stab or pierce with a pointed object”—as in “stick a knife in the potato to see if it’s cooked”. This definition describes the basic situation—someone using a pointed object to pierce something—but other senses can emphasize different parts of this basic situation or extend it in various ways. The result is a complex web of related senses.
If you pierce something with a pointed object, you will probably make a hole, so we can say “stick a hole in it” or “it was stuck full of holes”. Here the focus is on the substance being pierced rather than the object doing the piercing.
Most often the pointed object moves towards another object—as in “stick the knife into the potato”—but sometimes the other object moves towards the pointed object so that it becomes impaled—“now stick the pieces of meat and vegetables onto the skewer”. Another sense emphasizes the motion, rather than the pointed shape of the object—“stick this in your pocket”.
The focus of the action may be not so much the action of piercing but the result of the action—“to fasten (something pointed) in position by thrusting its point into a surface”—“I stuck the thermometer into the roast”. The focus of attention may be the pointed object itself—“to be fixed or embedded in something by piercing” and “to be secured or held by having one end inserted in something”; in this sense the verb often shows up as the past participle—“the needle got stuck in the fabric”.
The basic situation can also be extended, if the pointed object is used to stick something to something else—“stick the list to the board with a thumb tack”. Here the list may be the focus of attention, and the pointed object—the thumb tack—may be just an accessory implement.
If you stick something into something it may stay there; this sense leads to the idea of fixing something permanently in place, and in this sense the idea of a pointed object may be lost as the idea of permanent or prolonged fixation dominates; thus “stick the list to the wall with tape”, where the tape is not a pointed object and it doesn’t pierce the wall. This sense leads to the adjective “sticky”—something may stick because it is sticky, not because a pointed object is piercing anything. This stickiness may be figurative—“that song stuck in my mind”. The idea of permanent or prolonged fixation can also be figurative—“We were stuck at the airport for twelve hours”; “will the charges against him stick?”
The word shows up in many more or less idiomatic phrases: “stick ’em up!”; “I couldn’t say that, the words stuck in my throat”; “don’t stick your neck out”; “he stuck out like a sore thumb”; “let’s stick together”; “you should stick to your guns”; “that dinner will stick to your ribs”; “she stuck up for me”; “I was stuck with a boring job”. Each of these fits or changes or extends the basic situation.
The word “stick” is also related to the word “stitch”, both noun and verb—when you stitch you use a pointed object, a needle, to pierce another object, cloth, but in addition the needle is attached to a thread and typically you take several stitches in a row. Medical stitches are similar, but with special needles and thread. Another related word is “steak”; originally “steak” was meat pierced by a skewer and roasted, but then the word was applied to roasted meat in general and then to the cut we think of as a steak today. (But the word “stake”, according to Watkins, comes from a different Proto-Indo-European root, “*steg”, rather than “*steig”.)
The root “*steig” shows up in the Greek verb “stizdo” (στίζω; the root is “stig-”), which means generally “to pierce or puncture” and more specifically “to tattoo” or “to mark as one’s property”, that is, “to brand”. The noun “stigma” (στίγμα, derived from the verb root “stig-” by the addition of the suffix “-ma”) means “a prick or puncture made with a sharp instrument” and more specifically “a tattoo” or “a mark or spot”. In Greek a stigma is usually a bad thing, a mark of subjugation. In English the word “stigma” can mean “a mark on the skin” or “the visible sign of a disease”, but more commonly it means “a mark or sign of disgrace or discredit”, either literally or figuratively; the plural form “stigmata” can mean “marks resembling the wounds left on the body of Jesus as a result of his crucifixion”, especially on the bodies of saints or other devout persons. The word also has various specialized medical or scientific meanings. The verb “stigmatize” means “to mark with a brand” or “to describe as discreditable or undesirable”, either literally or figuratively. The word “astigmatism” was coined by William Whewell in 1846; astigmatism occurs when the light rays entering the eye don’t come to a point, so the eye is unable to focus properly.
In Latin, the root “stig-” shows up in the verb “instigo”, which means “to goad, incite, stimulate”—presumably by using a sharp stick, that is, a goad (the Latin word for “a goad” is “stimulus”), and thus the English “instigate”.
The English words “ticket” and “etiquette” also come from the same Proto-Indo-European root. English borrowed the noun “ticket” from French in the sixteenth century. The French word was “étique”, with the meaning “a little note”, particularly a short public notice; this word came from the verb “estiquer”, which meant “to stick on”, so an “étique” was a note stuck, for example, to a wall as a public notice. (The word “étique” has dropped out of modern French, which might use “billet” for “ticket”.) The French word probably derives from Proto-Germanic “stikkan”. French first added an “e” to the beginning of the root and then dropped the “s” after the “e”. Thus the form with “stik-” became “estik-” which then became “etik-”, spelled “etique-”. (We see this process in other French words, such as “étude”, from “estud-”, from “stud-”, which goes back to the Latin “stadium”, and “école”, from “escole”, which goes back to Greek “schol-”, and many others.) The French “étiquette” derives from “estiquette”, which could mean a short note with instructions directing proper behavior, either at the French court or in military lodgings. Modern French “étiquette” means “a small label which one puts on an object to indicate its price, contents, etc.”, while the English word means something like “the rules of proper behaviour”.
Thus the Proto-Indo-European root “steig-” is the basis for a family of related words in English—“stick”, “stitch”, “steak”, “stigma”, “stigmatize”, “astigmatism”, “instigate”, “ticket”, and “etiquette”—all going back to the idea of piercing something with a pointed object.