suffix
Suffix used in compound words to indicate the middle or center of something, such as in 中央 (ちゅうおう, center) or 震央 (しんおう, epicenter). Not used as a standalone word.
「中央」の「央」は真ん中を意味する。
The 央 in 中央 means 'middle'.
震央は地震の発生地点の真上の地表の点だ。
The epicenter is the point on the earth's surface directly above the origin of an earthquake.