When someone says they have completed Shas or learn Shas, what is Shas? Thanks.

Shas are the six sections of the Oral Torah, each one is called a Seder. Each Seder has a general subject it discusses, and is devided into smaller parts - each a Masechet. The Masechtot discuss more specific subjects. The Shas has mainly two parts - the Mishna which is the base of the oral Torah, and the Gemarra, or Talmud, which is an explanation and elaboration of the Mishna. Learning, or completing Shas could mean either Shas of Mishna, or Shas of Talmud. Sincerely, WWW.YESHIVA.ORG.IL