simultaneity
🇺🇸
/ˌsaɪmltəˈniːəti/
🇬🇧
/ˌsɪmltəˈneɪəti/
The state of two or more things happening at the same time.
The simultaneity of the fireworks display and the singing of the national anthem was a memorable moment.
煙火表演和國歌演唱的同時發生是一個難忘的時刻。