Hi chuhung, and thanks for the question!
According to my dictionary (Macquaire Dictionary, 2nd Ed):
Hi-fi, 1. => High-Fidelity 2. A High-fidelity record player, etc.
Hi-fi system, 1. A high-quality audio system for the home
This definition is supported when searched at www.Dictionary.com and
However, "Hi-end" is a word that appears in none of the three
dictionaries - I believe it is a word that has been generated
commercially (apparently catchy?).
But when I searched "what is Hi-end audio" at google, I struck this
site, which seems to raise an interesting argument:
"Hi-End audio as I define it is the collection of equipment and source
material dedicated to the high fidelity reproduction of music. This
differs greatly from 'Hi-Fi' which is a marketing cliché typically
used by people who have little interest in the fidelity of their
equipment. Unfortunately, few people are aware that Hi-End audio even
exists. Most people believe Polk, Carver, Bosé , Onkyo, etc. represent
the high end when in fact a whole industry lies above these 'Mid-Fi'
brands. There are actually hundreds of companies, primarily U.S.
based, producing low volume, often hand-assembled equipment. Few
people have heard of Krell, Thiel, Apogee, or Mark Levinson which are
all intimately well know within the industry. Among these brands,
fancy features, lights, and frills are usually abandoned in order to
devote full attention to the most important product feature... the
World of BS: Hi-End Audio
This site is definitely worth a visit in regard to your question.
This site outlines that Hi-end is a term used to describe equipment
that produces the best quality sound (high-fidelity), but the term
Hi-Fi has become a marketing tool, not necessarily representing
high-fidelity equipment, despite the linguistic connection.
Yet the site continues that the quality of sound is subjective, and
thus the discernment between these terms are difficult and may vary
from person to person.
I hope this answers your question, and if you are not satisfied,
please feel free to ask for clarification. I learnt a lot through
your question - thanks!