From The Free On-line Dictionary of Computing (19 January 2023):
ELP
1. English Language Programs. Language for testing avionics
equipment, on Varian 620/i.
"Multiband Automatic test Equipment - A Computer Controlled
Checkout System", T. Kuroda et al, Proc SJCC, 38 (1971).
2. Equational Logic Programming. A semantically pure, fully
lazy language by M.J. O'Donnell <odonnell@cs.uchicago.edu>.
Sun and DEC versions
(ftp://gargoyle.uchicago.edu/pub/equations/eq4.2.tar.Z).
["Equational Logic as a Programming Language", M.J. O'Donnell,
MIT Press 1985].