秒 is also used as internet slang meaning 'instantly': 秒杀 (miǎoshā) = 'instant kill' / sell out instantly; 秒回 (miǎo huí) = reply instantly; 秒懂 (miǎo dǒng) = understand immediately.
usage
Time units: 秒 (second), 分钟 (fēnzhōng, minute), 小时 (xiǎoshí, hour).
