What is the meaning of ?

a staff, measuring 6 shaku (about 1.8 meters), used in martial arts such as 棒術 (bōjutsu)

stick-like or long, cylindrical item: pointer, pole, rod, etc.

a straight line; bar

state of being in a "straight line"; continuous

taut leg muscles due to fatigue (Can we verify this sense?)

staff used by practitioners of Zen Buddhism

Source: wiktionary.org