Bad: synopsys

Good: synopsis

I have two ways to remember the spelling this word.

First is to remember to spell the word, synopSIS like sounds, ie:  SIS at the end.

Second is that a lot of times the synopsis is a sister document included with a query letter when a writer is submitting a manuscript to an editor or agent. Thus, synopSIS is a SISter document .

If you have alternative ideas, please provide them in the comment section of this blog