What does -sch- mean?

-sch- meaning in Etymology Dictionary

this letter group can portray five distinct sounds in English; it first had been employed by Middle English writers to render Old English sc-, the pronunciation that then simplified to "-sh-" (an evolution that also took place in Middle Dutch and Middle High German). Often it was miswritten for -ch-. Moreover it was used from German (schnapps) and Yiddish (schlemiel). In words produced from classical languages, it presents Latin sch-, Greek skh- but in a few of these words (eg schism) the English spelling is a restoration in addition to pronunciation does not follow it.