noun
Refers to a geographical or magnetic pole, or the terminal point of an axis. Common in compounds like 北極 (North Pole) and 南極 (South Pole).
地球の北極と南極は氷で覆われている。
The Earth's North and South Poles are covered with ice.
noun
extreme; climax; zenith; nadir
Denotes the furthest point, highest degree, or culmination of something. Can be used for both positive and negative extremes (zenith/nadir). Often appears in phrases like 極に達する (reach an extreme) or 極を尽くす (exhaust all extremes).
彼の怒りは極に達した。
His anger reached its peak.
この贅沢は極を尽くしている。
This luxury is the ultimate extreme.
The kanji 極 originally depicts a beam or ridgepole, extended to mean the utmost point or extremity. The reading きょく is the on'yomi.