Brother Bob,
2 Thessalonians 1:9 strongly suggests that the Greek word apo is used to denote origin, as it does in v. 2: “Grace unto you, and peace, from (apo) God our Father and the Lord Jesus Christ.” That this is the case is evident from the fact that the destruction is explicitly said to come about via the fire of God (v.8). Thus, it stands to reason that the destruction is eternal by virtue of the fact that it orginates in the eternal God. This idea is articulated here:
"And fear not them which kill the body, but are not able to kill the soul: but rather fear him which is able to destroy both soul and body in hell." Matthew 10:28
Eternal destruction and eternal punishment are eternal in that they are the kind of destruction and punishment that only God is fit to bring about.