Paul's letter to the church at Colossae, called Colossians, is not related to the name of the Colossus of Rhodes, about the height of the Statue of Liberty (not including the base) and one of the seven wonders of the ancient (Greek-centered) world.

There are many ideas of the origin of the city name of "Κολοσσαί" ≈ "Colossae".

The ancient Greek word "ὁ Κολοσσὸς Ῥόδιος" ≈ "Colossus of Rhodes". The large statue there became the basis of the English word "colossal" through the ancient Greek word "κολοσσός" ≈ "large statue". The origin of this name is not known.
It is not clear if the Greek name "Colossus" is related to "κόλον" ≈ "intestine, food, fodder" or "κόλος" ≈ "parts or extremities removed".

More: A colonoscopy of an annoying and disturbing difficulty

Like many cities, Colossae had an acropolis - a (high) point at the end of a mountain ridge.

Colossae had a theater, temple, etc.