From The Free On-line Dictionary of Computing (19 Sep 2003) [foldoc]:
HLL
high-level language
From Jargon File (4.4.4, 14 Aug 2003) [jargon]:
HLL
/H.L.L/, n.
[High-Level Language (as opposed to assembler)] Found primarily in
email and news rather than speech. Rarely, the variants `VHLL' and
`MLL' are found. VHLL stands for `Very-High-Level Language' and is
used to describe a bondage-and-discipline language that the speaker
happens to like; Prolog and Backus's FP are often called VHLLs. `MLL'
stands for `Medium-Level Language' and is sometimes used
half-jokingly to describe C, alluding to its `structured-assembler'
image. See also languages of choice.