Cassandra - Claims construction hearings are appealed as pure questions of law - thus the appeal is de novo - meaning starting fresh - if it was an issue of fact, them the appellate lawyer would need to comb through the trail record and find errors on the part of the trail court, etc...
Chief Judge Mayer stated as follows: "Until the court is willing to reconsider its holdings in Markman v. Westview... that claim construction is a pure question of law subject to de novo review in this court, any attempt to refine the process is futile. Nearly a decade of confusion has resulted from the fiction that claim construction is a matter of law, when it is obvious that it depends on underlying factual determinations which, like all factual questions if disputed, are the province of the trial court, reviewable on appeal for clear error. To pretend otherwise inspires cynicism. Therefore, and because I am convinced that shuffling our current precedent merely continues a charade, I dissent from the en banc order."
I have included some basic information that may assist you in understanding the difference between a regular appeal and a de novo type situation.
Standards of Review -
"Appeals courts in the U.S. legal system generally apply one of three standards of review to decisions from lower courts. The "arbitrary and capricious" or "abuse of discretion" standard is applied when reviewing the decision of an administrative agency. The appeals court will only overturn an agency decision if it was arbitrary and capricious, or if it exceeds the agency's lawful authority. If the appeals court applies the "clearly erroneous standard," it will only overturn the lower decision if it contains plain errors of fact or law. Both these standards are deferential to the lower court decision. The de novo standard affords no deference to the lower court."
Definition
"The phrase "de novo" is a latin term meaning "anew" or "afresh." When appellate courts apply the de novo standard of review, they hear the case all over again, as if it had not previously been tried. The de novo standard of review may be applied to the law of the case, the facts of the case, or both."
What I posted previously is not erroneous as you unfairly claim of course, but speaks to the difference between these legal fictions - good luck in figuring this out.