A Greek term that is often debated when discussing Jesus' entry into the heavenly sanctuary is the term ta hagia.  The term is actually the adjective holy and is used in various forms in Hebrews, primarily as a substantive, or noun, describing  the holy place.

The term has been translated a number of ways in the different verses of Hebrews. Some Bible versions are more consistent than others in their translation of the word.

The debate is whether the term refers to

a. the holy place
b. the most holy place
c. the whole sanctuary.

I have taken the same position as the Adventist scholars on the Daniel and Revelation Committe who studied the Hebrews material. Their summary is given below:

The committee believes that ta hagia should be regarded as a general term that should be translated in most instances as “sanctuary” unless the context clearly indicates otherwise (such as in chapter 9:2, 3).
("Daniel and Revelation Committee Report," Issues in the
Book of Hebrews, 5

For more information on evidence for the term most often referring to the whole sanctuary, the reader is directed to the article of Alwyn P. Salom, "Ta Hagia in the Epistle to the Hebrews." This article originally appeared in the Andrews University Seminary Studies and was reprinted in Issues in the Book of Hebrews as an appendix.

You can read it online, hosted in the archives of the Andrews University Seminary Studies: