Definition - What does Loka mean?
Loka is a Sanskrit term meaning "world" or "a particular division of the universe." The most frequent division of the universe in Hinduism is the tri-loka: Earth, heaven and atmosphere.
Some sources consider there to be 14 worlds. These are the seven higher worlds, found above the Earth; and the seven lower worlds, found beneath the Earth.
Yogapedia explains Loka
The seven higher lokas, called vyahrtis, are all linked with a chakra and represent the spiritual development of humans. The seven lower lokas, called patalas, exist for those with a lower degree of consciousness and low control. The Earth is thought to be the lowest of the seven higher worlds. The other higher worlds are home to Brahma, the sons of Brahma, other gods and goddesses, rishis, sages and the sun. The seven lower worlds are home mostly to demons and foes.
The world that humans currently live in is called bhu-loka, the root, associated with the muladhara (root) chakra.