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bone
frame
outline; core
backbone; spirit; fortitude
laborious; troublesome; difficult
「骨」 has another reading with different meanings.
魚の細い骨が喉に刺さってしまった。
A fish bone stuck in my throat.
強風で傘の骨が一本折れてしまった。
One of the umbrella's ribs broke in the strong wind.
骨に良い食事を心がける。
I try to eat meals that are good for bones.