Recently I read about a nice description of the various levels of lucidity:
Nonlucidity: people respond to a dream situation as if it were real
Tacit Lucidity: the dreamer acts as if he/she is lucid without actually being lucid. The dreamer doesn’t know that he/she knows. A subtype of the tacitly LD is when you recognize the dream plot as being unreal, but you perceive the action as a television show or movie that you were watching or in which you had a part. Sometimes you may also interprete the dream as a story you are making up.
Prelucidity: the dreamer begins to suspect that he/she is dreaming.
Postlucidity: the dreamer becomes aware that he/she was recently dreaming, without being aware that he/she is still dreaming. This situation is very common after you have a false awakening.
Semilucidity: you realize you’re dreaming without understanding the full significance of that fact. There’s a whole range of levels of semilucidity.
Dream within a dream: this can happen when you fall asleep in a non-lucid dream and then become lucid in the following dream within the dream. This ain’t full lucidity because you think you went to bed in real life. WILDs which occur during falling asleep inside a dream seem to develop much faster than irl, but otherwise they are indistinguishable from regular WILDs.
Full Lucidity: this is actually pretty rare. You FULLY understand the implications of your lucidity. You’re able to morph the dream scape in whatever setting you wish.
Protolucidity: when the dreamer becomes aware of the state he/she’s in while observing hypnagogic/hypnopompic hallucinations, or when one’s asleep (so-called lucid sleeping). Again there are many variations of this type, such as tacitly protolucidity.
Source: Janice Brooks & Jay Vogelsong - “The Conscious Exploration of Dreaming”
All these types are very hard to distinguish while in a dream: they flow into each other because these types cannot be pinpointed down to one specific moment. They form a continuous spectrum, going from non-lucidity to full lucidity. While you may decide that you’re semi-lucid to some degree at some point in the dream, the dream consciousness is constantly shifting on the lucidity spectrum, often showing only very subtle changes. The one moment you may be semi-lucid to various degrees, while the next moment you’re back prelucid or non-lucid, and so on…