Norman Hubbard:

Put yourself in the shoes of a traveler to ancient Tyre, a city conveniently located where the modern city of Tyre is, in Lebanon. How would you find a church in the first century? There would be no signs. The mechanic at the local Tyre Shop probably couldn’t help. You couldn’t even ask for a “church.” The word “church” (ekklesia in Greek) was a common term that meant “civic gathering.”

You could also forget about asking where the “Christians” gathered. For a time, no one used this term at all. When it came onto the scene (see Acts 11:26), it was almost certainly a slur. In some cases, it could have been lodged as a criminal accusation (see 1 Peter 4:15-16). Asking someone at the Tyre Shop where to find a “Christian church” might have sounded like you were searching for a civic gathering of anti-imperial agitators.

So if you wanted to find a Christian church 2,000 years ago in places like Tyre, you could start by asking where the Jewish synagogue was…. But how would you know whether the synagogue assembly was a group of Christians? You could start by looking at the composition of the group and then listen to what they called each other.