simultaneously concurrently
Simultaneously.
The word is contemporary.
simultaneously
Once
There are a few one word that mean the same thing as called off. You can used the word quit, out or time.
Happening one time and since the word once is almost like one. One and once almost have the same meaning that will also help you.
punctual
Having two wives at one time is "bigamy" (illegal in the US, but common in some societies). The general word for having more than one wife is polygamy.
There is one syllable in the word same.
coincidence
People of the same time period are referred to as contemporaries.
Concurrent
"Simultaneous"