also: さなか
in the middle of; in the midst of; at the height of
Indicates being in the middle of an action, event, or state. Often used with nouns or verbs in the ている form. The reading さなか is more formal/literary.
The phone rang in the middle of the meeting.
He was in the middle of a meal.
The ship left the harbor in the midst of the storm.
The phone rang right in the middle of the meeting.
An earthquake struck while we were in the middle of eating.
I'm right in the middle of important work now, so let's talk later.
最中 means simply 'in the middle of' any event or action, while 渦中 specifically implies being caught up in trouble, scandal, or swirling turmoil.
最中（さいちゅう）is a noun meaning 'right in the middle of' used with の, whereas 中（ちゅう）is a suffix attached directly to action nouns like 会議中.
最中 (〜している最中に) describes something happening while an action is still ongoing, whereas 矢先 (〜した矢先に) marks the instant right after an action is completed.
最中 emphasizes being right in the middle of an ongoing action, whereas その間 covers the whole duration between two points.
最中 stresses being right in the peak or thick of an action at this moment, whereas 途上 describes a longer-term process still underway.
Rare variant spelling using kana for the first character. Not commonly used.