A label for almost anything
In everyday English, thing is the all-purpose stand-in. It can mean an unnamed object, an event, a problem, a possession, or a living creature spoken of with pity or fondness. People pack their things, have a thing about loud rooms, and reduce a messy situation to this whole thing. The word sounds empty on purpose: it fills a slot when a more exact noun is missing or unwanted. That emptiness is young compared with the history behind it. English did not invent a blank token. It inherited a Germanic noun that once named a meeting of people, then the business of that meeting, and only later the mute object on the table.
Inherited, not borrowed
The path into English is native. Middle English thing continues Old English þing, also spelled þingc in some manuscripts. The noun is already in use in the Old English period, before 1150. In that stage it covered several related ideas at once: a meeting, council, or discussion; an action or deed still to be done; and, by late Old English, a concrete inanimate object, an entity or creature, and an event.
The oldest layer is the gathering. Speakers could talk of holding a þing, a deliberative or judicial assembly. In Beowulf the hero must hold a þing with Grendel: the word there is a confrontation between opponents, not a chair or a stone. By early Middle English that civic sense had dropped out of ordinary speech. A remnant survives in the second half of hustings, from Old Norse húsþing, a house assembly or council held by a lord. Later English revived thing as a historical term for the old Germanic court, largely under the influence of Scandinavian cognates. When a modern writer mentions a Norse thing, that usage is a learned return of a meaning English had already lost.
From a set time to a council
Comparative evidence reconstructs Proto-Germanic *þingą (some handbooks write *þingaz), reached in English through Proto-West Germanic *þing. The family is wide: Old Frisian thing, Old Saxon thing, Middle Dutch dinc and modern Dutch ding, Old High German ding and German Ding, Old Norse þing, and the later Scandinavian forms Icelandic þing and Norwegian, Danish, and Swedish ting.
Most accounts take an earlier sense of appointed or suitable time as the starting point. Gothic, often conservative in meaning, has the related noun þeihs for an occasion or a stretch of time, from a closely allied Germanic form. What lies behind that time-word is disputed. One line, associated with Watkins and Boutkan, connects it with a root *tenk- from *ten-, to stretch, and pictures a stretch of time reserved for a gathering. Another, in Kroonen’s dictionary of Proto-Germanic, prefers *tenk- in the sense to be suitable or to succeed, so the first meaning would be a suitable or scheduled moment that then became the meeting held at that moment. Both stories agree that the calendar sense came first and the council second. They do not agree on the ancestral verb, and that disagreement should stay on the page: the deeper Indo-European step is a reconstruction, not a recorded English fact.
From the meeting, the next shift is widely accepted. The matter laid before the assembly became a thing in its own right. The same kind of drift shows up in neighboring traditions. Latin res meant a legal case as well as an affair or an object. Latin causa, a lawsuit or case, yielded French chose and Spanish cosa, both used for an ordinary thing. Germanic *sakō, the source of English sake, moved from dispute toward affair. English thing belongs with that pattern: courtroom language thinning into a word for whatever is at issue, then for whatever exists.
How the senses opened
Once the noun could name the business of a council, it could name almost any concern. Around 1300 it is recorded as a matter of interest or a side taken in a controversy. In the fourteenth century it also appears as a cause, an occasion, and a justification for an action. The inanimate-object sense, already available in late Old English, became the default in later centuries.
Other offshoots are dated more tightly. Early in the twelfth century the word could refer to a living person, often affectionately or pityingly; the collocation young thing is recorded from about 1200. From around 1600 speakers used it colloquially for an object they could not or would not name at the moment, which later fed playful extensions such as thingamajig. None of these uses required a new root. They are the old legal noun stretching until it can stand for an unnamed cup, a person, or a feeling.
The political sense did not vanish from the Germanic world. It simply stayed north. Iceland’s Althing, in Icelandic Alþingi, is the general assembly, founded in the tenth century at Þingvellir, the assembly fields. Norway’s Storting is the great assembly. English kept the leftover object and dropped the gathering from daily use, except in hustings and in the historical term borrowed back from its cousins.
What the map still shows
The origin of the word thing is easiest to see on a Scandinavian map. Þingvellir is still the fields of the assembly, not a pile of objects. English speakers kept the case that used to be argued there and forgot the meeting itself. The vagueness of the modern noun is not a blank invented for convenience. It is what remains after a scheduled gathering, then a lawsuit, then an affair, had all worn down into any item you have not bothered to name.