Apologies if I misunderstood your post and you already know this.
Pascha and Easter are the same holy day. That’s why Good Friday, Holy Saturday and Easter Sunday are known collectively among liturgical Christian churches as the Paschal Tridiuum.
Here’s a brief history on the topic from OrthoWiki:
http://orthodoxwiki.org/Pascha
Also Holy Thursday, which honors the Lord’s Last Supper and the washing of the feet to make the Easter Tridium.