Where does “רש״י” come from?

רש״י (Yiddish) comes from Hebrew רש״י, from Hebrew רַבִּי שְׁלֹמֹה יִצְחָקִי.

Ancestry of “רש״י”, step by step

Step	Language	Word	Meaning
1	Hebrew	רש״י	—
2	Hebrew	רַבִּי שְׁלֹמֹה יִצְחָקִי	—