J-L wrote (on the Yahoo DzogchenPractices list regarding the
etymology of Trekcho:

Basically Khregs refers to'rigidity' or hardness, and chod
pa means 'to cut', 'to eradicate'. It is short for Khregs-
se chod-pa, which indicates both a process and a state,
meaning 'Eradication of the Rigidity'. You can put whatever
you want under Rigidity: ego-grasping, mental elaboration,
passions, ignorance, etc.

Comment:
J-L, first of all many thanks for your efforts to shed light on
some of these amazing practices. Your quote re: “Eradication of
Rigidity” reminded me of something I thought about once regarding
the saintly Ramana Maharshi’s teenage decision to find out what
it was to die. I realized that, as a Hindu, he had more familiarity
with dead bodies than we have in our so-called ‘advanced’ countries,
and would have understood how a body stiffens into rigor mortis.
Thus his attempt to duplicate death would have included the
stiffening of all his muscles. I recently found verification of
this in a quote from his description of the event as follows.
Various versions can be found on line.

The shock of the fear of death drove my mind inward and I
said to myself mentally, without actually framing the words,
'Now death has come; what does it mean? What is it that is
dying?... This body dies.'
I at once dramatized the occurrence of death. I lay with my
limbs stretched out stiff, as though 'rigor mortis' had set
in and imitated a corpse so as to give greater reality to
the inquiry. I held my breath and kept my lips tightly closed
so that no sound could escape, so that neither the word 'I'
nor any other word could be uttered.
'Well then,' I said to myself, 'this body is dead. It will
be carried stiff to the burning ground and there burnt and
reduced to ashes. But with the death of this body am I dead?
Is this body I? It is silent and inert but I feel the full
force of my personality, and even the voice of "I" within me,
apart from it. So I am Spirit, transcending the body. The body
dies, but the Spirit that transcends it cannot be touched by
death. That means I am the deathless Spirit.'
All this was not dull thought; [rather] it flashed through me
vividly as living truth which I perceived directly, almost
without thought-process. 'I' was something very real, the only
real thing about my present state, and all the conscious
activity connected with my body was centered on that 'I'.
From that moment onward, the 'I' or Self focused attention on
itself by a powerful fascination. Fear of death had vanished,
once and for all. Absorption in the Self continued unbroken
from that time on.

Comment:
Rigidity, concentration, fixation – all these words point me towards
an application of the will that seems necessary first of all before
one can relax and still retain ‘focus,’ as it were. This topic came
up earlier in DzogchenPractices in the discussion on Zhine and the
need to fix the gaze without blinking on the meditation object. This
comes up of course in Patanjali’s ‘tratak’ exercise as well as in
some Theravada Buddhist exercises involving fixation on a ‘kasina,’
more or less a mandala, until the afterimage is burned into one’s
awareness. It seems to me that Dzogchen’s “relaxation” and Trekcho’s “relaxation of rigidity” implies a previous state of intense applica-
tion of the will to develop one-pointedness to a permanent stage –
after which the ‘relaxation of rigidity’ makes great sense, but not
before. Thank you again! Very helpful!