Mythical (adjective)

1. Related to myths or legends.
2. Having a legendary or traditional quality.
3. Fabled or imaginary and not based on fact.

Origin:

From latin mythicus, from greek mythikos, from mythos "myth".

Examples:

1. The city of Atlantis is a mythical place.
2. The dragon is a mythical creature that appears in many cultures' folklore.
3. The sword of King Arthur is a mythical relic.
4. The quest for the Holy Grail is a mythical tale that has captured the imagination of many.
5. The creature in the lake was said to be a mythical beast, but no one had ever seen it.