What does trepan mean?
Trepan is a specialized medical word with two closely related uses. As a verb, it means to perforate a person's skull, traditionally to relieve pressure, remove blood or tissue, or treat a cranial injury. As a noun, it can denote the surgical instrument used to make such an opening, often called a trephine, or the operation itself, better known as trepanation or trephination. These practices have a long and sometimes disturbing history, and the word consequently carries clinical and historical associations alongside its technical function. In current English, trepan is much less common in everyday speech than words such as surgery, but it remains useful in medical, historical, and archaeological discussion, including accounts of ancient skull-opening procedures. Its unusual pronunciation and its connection with one of medicine's most dramatic operations make it memorable, though specialists generally prefer more precise terms when describing the instrument, procedure, or method.
To perforate a person's skull, especially with a surgical instrument.
"The physician trepanned the patient's skull to reduce the pressure inside the cranial cavity."
Now uncommon and largely confined to medical, historical, and archaeological contexts.
A surgical instrument used to open the skull, or the operation of perforating the skull.
"The museum preserves several antique trepans used to open the skull."
The instrument is often called a trephine, while the operation is usually called trepanation or trephination.
The standard plural of the noun; plural inflection is uncommon because the word is specialized.
"The collection includes two trepans made for cranial surgery."
Trepan records one of medicine's most dramatic interventions: opening the skull itself.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does trepan come from?
The word came into English from French trépan, which was borrowed from Medieval Latin trepanum. This in turn came from Greek trýpanon, an auger or drill, belonging to a Greek root meaning 'to bore'. English trephine, trepanation, and trephination preserve the same historical boring connection, although trephine was reshaped under the influence of Greek trēphō, 'I bore'.
Related word forms
How trepan is actually used
Rare and specialized in modern English, occurring chiefly in medical, historical, archaeological, and antiquarian contexts. The noun and verb have different pronunciations in some major dictionaries; the related terms trepanation, trephination, and trephine are often preferred for greater precision.
Easily confused with trepan
A trephine is specifically the cutting instrument used to open the skull; trepan chiefly denotes the operation or act of skull perforation, though it can also refer to the instrument.