also: むらだち
noun
standing up together; rising as a group
Describes a crowd or audience all standing up at once, often in excitement, applause, or protest. The reading そうだち is standard; むらだち is rare.
観客が総立ちで拍手を送った。
The audience gave a standing ovation, all rising to their feet.
彼の演説が終わると、会場は総立ちになった。
When his speech ended, the whole hall rose to their feet.
起立 is a formal term for standing up, often used in commands or official settings. 総立ち emphasizes the collective, simultaneous action of a group.
Compound of 総 (all, together) and 立ち (standing). The spelling 叢立ち uses 叢 (cluster, thicket) to convey a group, while 群立ち uses 群 (crowd). The reading そうだち is the standard modern form.