The Free On-line Dictionary of Computing (19 January 2023):

loop
loop through

    A sequence of instructions in a program that
   the processor repeats.  The loop will usually terminate when
   some condition is met or it may run indefinitely - an
   infinite loop.

   Structured languages like C and its descendents provide
   loop statements and keywords for some or all of for
   loop, while loop and repeat loop.  See also
   loop-and-a-half.

   In other languages these constructs may be synthesised with a
   jump (assembly language) or a GOTO (early Fortran or
   BASIC).

   To "loop through" a list means to process each element in turn.

   (2019-09-03)


The Jargon File (version 4.4.7, 29 Dec 2003):

loop through
 vt.

    To process each element of a list of things. “Hold on, I've got to loop
    through my paper mail.” Derives from the computer-language notion of an
    iterative loop; compare cdr down (under cdr), which is less common among
    C and Unix programmers. ITS hackers used to say IRP over after an obscure
    pseudo-op in the MIDAS PDP-10 assembler (the same IRP op can nowadays be
    found in Microsoft's assembler).