正当中

• 一(straight line; boundary; destination)ASSOCIATIVE
• 止(stop; foot)RADICAL

A foot stopping exactly at the line is straightness and precision.

• 口(mouth; sound)RADICAL
• 當(equivalent; opportune)PHONETIC

The sound of a bell ringing from an opening makes a "clanging" noise that rings out at just the right moment.

• 口(mouth; rectangular frame)ASSOCIATIVE
• 丨(vertical line through the middle; axis)ASSOCIATIVE

An arrow hitting the center of a target frame is the bull's-eye—that's CENTER.