The word heaven is used very frequently in the bible. Many people just automatically assume that each case always refers to the same thing. They assume there is only one meaning of the word. However, that translation is used to represent several different original ideas.
Like a host of other English words, “heaven” has been used for several meanings. At times it is used to refer to the general space in the atmosphere surrounding earth. In other words, it’s referring to the sky: clouds, birds rain etc. all reside in the “heavens.” It can also mean the space beyond our atmosphere (aka outer space) in which resides “heavenly” bodies such as the stars, sun, moon, and planets. Thirdly, it can be used to refer to the conceptual residence of God. I think of it as a wholly different plane of existence separate from time and space, but we will only ever fully understand it when we actually experience it.
In this light, the biblical heaven could also be considered as having several “levels” of existence. The first level would be considered the immediate atmosphere. The next, “higher” level would be considered to be outer space and its inhabitants. Finally, the highest level is of course the dwelling place of God.
Also worth noting is that in some cases “heaven” can be used to refer to God himself, as something of a code word. It is important to understand these terms in their context when reading scripture. Otherwise a certain verse or passage could be misinterpreted and cause dangerous or contradictory implications.