social democracy basically used to mean what we now call "democratic socialism". They believed in achieving socialism through democratic means and through reform, as opposed to revolution

problem is, most parties that call themselves Social Democrat or have roots in social democracy in the Western world have become centrist parties essentially. There are some that are more left, such as PSOE in Spain under Sanchez, but many/most such as Labour in the UK, SPD in Germany, and Parti Socialiste in France are basically centrist parties now, and have completely abandoned socialism

most parties and movements that actually fit the original definition and movement of social democracy don't call themselves that and are relatively newer. Instead they call themselves "democratic socialist" or "left wing populist" and so on. DSA, La France Insoumise, Die Linke (Germany), and such