Is there any symbol denoting a synonym?

I like writing down the synonyms of words, but writing "is synonym to" all the time feels wasteful.

Is there some short symbol for it? Right now, I'm using "==", as in "OP == fag, opening_poster, first_poster". So, I tried searching for it, but all I get is actual synonyms of the other words I type in. Then I tried looking up what a synonym actually is and find a symbol from there, but it all got very confusing when I got into terms like extension, intension, connotation, strict synonym, partial synonym, hyponym, symmetry, reflexivity, transitivity...

Maybe I should rather ask: What are all the popular ways to symbolize equivalency within their respective fields?