The word "simulance" is indeed a valid English word and can be found in most major dictionaries. It means "the state of being similar or alike" or "the simultaneous occurrence of two or more similar events or things." It is derived from the Latin word "simulans," which means "imitating" or "resembling."
Here are some examples of how the word "simulance" is used in writing:
* "The simulance of their voices was uncanny."
* "The two paintings, while not identical, had a striking simulance."
* "The simulance of the two events suggested that they might be connected."