“Orthodox” today usually refers to the Eastern and Oriental Orthodox tradition. So in that sense it is a term for a spiritual culture as well as a faith/church. Historically, “Orthodox” was used to denote two things at once - right faith AND worship since the latter indicated the former. It was first formally used at the first Ecumenical Council in 325 AD when the Fathers affirmed the “Orthodox Faith” against Arius. It has been used to denote “true faith” ever since.
To be an Orthodox Christian meant that one believed in the true Apostolic faith as reflected in his or her worship. Both East and West used and continue to use that term.
“Orthodox” today refers to the Eastern Churches. But does “Orthodox Catholic” bring confusion? Following my old pastor, I would say not.
But doesn’t this term indicate either: a) a union between East and West that doesn’t yet exist? and/or b) an obfuscation of the relation of those Eastern Catholics who use that term with Rome, in other words, whether they are truly in union with Rome and not saying they are Orthodox Christians?
One may debate this, but the fact remains that in the EC liturgy, the term “Orthodox” is used all the time. It refers not only to our Eastern theological approach and faith, but also to the entire Eastern liturgical/faith culture in which our faith is imbedded.
The term “Eastern Catholic” is a rather weak term to underscore any of this. And especially since, in the West, the term “Catholic” is synonymous with “Roman Catholic” and the Latin ecclesial/liturgical culture.
When I try to explain my identity to many Roman Catholics and others, they often have no idea what I’m talking about. But when I say I’m “Orthodox Catholic” - then all the cobwebs seem to disappear. They are often not aware that there are Orthodox who became Catholics in union with Rome while keeping their rites and so on. So I will, as I’m often forced by the circumstances, to refer to myself as “Orthodox Catholic” to AVOID confusion.
Evhen Ivankiw of Sts Volodymyr and Olha parish in Chicago once recommended the UGCC adopt the term “Ukrainian Orthodox Catholic” and outlined his reasons. I agreed with him then and I still do.
As for issues that may arise from the use of such terminology, well, we will just have to educate RC’s and others about them.
Also, “Traditional Catholic” refers to the liturgical/spiritual culture of the Tridentine Catholic heritage although it can also refer to Catholics who are devoted to the Rosary and traditional devotions and who actually put into practice in their daily lives what the Church teaches . . .