枢

pivot; important part

Kanji 1464

The bolt called 枢 (くるる) slides into the cavity called 枢 (とぼそ), just as the knob called 枢 (とまら) fits into the hole called 枢 (とぼそ)! This apparent brain teaser actually supplies early meanings of 枢, which came to play a role in words for central things, ranging from the central nervous system to the center of political power. This kanji also pops up in terms for “Axis powers” and “axis of evil”!