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.
烟花表演和国歌演唱的同时发生是一个难忘的时刻。