a nonresident doctor or medical student; connected with a hospital but not living there
"The resident physician worked alongside an extern from another university who was spending the month observing at our clinic."
A person affiliated with an institution in a lesser capacity, for example, as a non-resident or as a part-time affiliate.
"In the global scope of my C program, I defined an extern int counter so that multiple functions could access and modify the same memory location without redeclaring it locally."
In the C and C++ programming languages, a variable that can be separately declared in many places, all of them referring to the same variable.
In plain English: An extern is someone who works at a company without getting paid to learn how things work there.
"The computer system crashed when an external program tried to access its files."
Usage: In programming contexts, use "extern" specifically when declaring variables that must be accessible across multiple source files. Outside of code, the term refers to someone affiliated with an institution in a limited capacity rather than holding full membership or residency.
External; outward; not inherent
"The actor's charm was an extern, carefully cultivated for the stage rather than a natural part of his personality."
In plain English: Something external is outside of you and not part of your own body or mind.
"The extern on duty checked all the doors before closing them for the night."
The word entered English from Middle French and ultimately traces back to the Latin externus, which originally meant being outside or external. Its meaning has remained consistent throughout its journey into modern usage.