A panel of jurors was originally a piece of paper on which the names of jurors were listed.
Last night, we learned Special Counsel Robert Mueller has impaneled a grand jury—which allows prosecutors to subpoena documents and ensures witnesses testify under oath—in his investigation into potential ties between Trump’s 2016 presidential campaign and Russia.
In the wake of the news, legal and political experts have been fielding the questions: “What does this panel mean for Mueller’s investigation? What does it mean for Trump?” Word nerds like me, meanwhile, are addressing a different query: “What, exactly, is impanel, and where does the word panel come from?”

A jury of your…tailors?
To impanel—or, in its older, early 15th-century form, empanel—is “to enroll someone onto a jury.” This verb, of course, is based on panel, “people assembled together to discuss or examine a particular matter,” especially a group of jurists.
Now, we might well imagine those jurists gathered around a large desk, seated behind a wooden barrier as prosecutors present evidence, or otherwise situated in some wood-lined room. Many US courtrooms indeed prominently feature wood panels. Perhaps we get a panel of jurists as a metaphorical extension of all the wood panels associated with their proceedings? It’s an educated guess. After all, consider how the bench refers to judges and the bar attorneys, both terms derived from prominent furniture in their historic work environments.
A similar process—technically called metonymy—does give us the juridical panel. It just has nothing to do with wood.
In the early 1300s, a panel was originally a “piece of cloth,” specifically one placed under a saddle to protect a horse’s back. Over the 14th century, the shape of such a panel of cloth, typically rectangular, was likened to other materials, like a pane of glass for windows.
By the start of the 1400s, panel was, in legal contexts, referring to a strip of paper or parchment on which the names of jurors were listed. The term panel went on to refer to a list of jurors, then a jury itself. By the late 16th century, panel had left the courtroom to name any list or group of people brought together to advise or decide on some business, e.g., a panel of experts.
On the basis of its thin, square shape and sectional use as a covering, panel was later applied to art (painting, 1680s; comics, 1920s), vehicles (carriages, 1760s), and electronics (late 1890s, with control panel by 1902).
Common threads
English borrowed panel from the French, which is ultimately a diminutive form of the Latin pannus, a “piece or garment of cloth.” Pannus also gives us a pane, which, though variously used of different kinds of sides and portions in its history, largely survives in windowpane or a pane of glass.
As for the deeper roots of pannus, Indo-European scholars point to the ancient *pan-, “fabric,” said to yield the Old English fana, a “flag or banner.” This became fane, then vane, as in a weathervane, rooftop wind-pointers we can imagine were originally flags or banners.
While weathervane and jury panels may be cut from a common “cloth,” the former turns in the direction of the wind; the latter, we hope, turns in the direction of the evidence.