Term:
Scooch (variant spellings: skooch, scootch, skootch)

Interest Group:
Rope assisted tree climbers.

Origin:
Colloquial English.
-- From Merriam-Webster's online dictionary:
(verb) : To move one's body, as in "scooch over," or to move something, as in "My cat always scooches things off counters".
-- From Yourdictionary.com:
1. to hunch or draw oneself up and move (through, down, etc.); "she scooched through the window and unlocked the door"; "he scooched down in his chair"
2. to slide as with short, jerky movements "scooch over and make room for me on the bench"

Proposed Meaning in Tree Climbing:
Noun: A unit of climbing motion while on rope, specifically, one cycle of motion upward in DdRT or SRT. In DdRT, to pull down on the free end of the rope, shift the friction hitch upward and prepare to repeat. In SRT, to pull oneself upward once and shift ascenders in whatever sequence is appropriate for the particular SRT variant. I've found myself using this more or less without thinking about it over the last year or so when climbing with others: "Why don't you do 2 more scooches so that you can sit on that branch over there", or "One more scooch and you should be able to brace your feet on the trunk." It's handy to have a word for this, and "scooch" just seems to feel right.
Verb: To perform a single scooch.