A spellingbee word:
therblig. One of the manual, visual, or mental elements into which an industrial manual operation may be analyzed in time and motion study. “The supervisor's goal was to eliminate one therblig at each station in the assembly line.”

I wonder where that one came from.

Backwards, therblig (kind of) reveals the person who coined the word. Used in the scientific management movement which was invented at the turn of the previous century by F W Taylor. The 'th' digraph is taken to be irreversible. From Frank Bunker Gilbreth.

http://www.bisso.com/ujg_archives/000219.html

Ah! "Cheaper By The Dozen" Gilbreth!