immersion

Short definition from Wiktionary

Noun

1. 1
   The act of immersing or the condition of being immersed: The total submerging of a person in water as an act of baptism.
2. 2
   The act of immersing or the condition of being immersed: Deep engagement in something.
3. 3
   An immersion heater.
4. 4
   A smooth map whose differential is everywhere injective, related to the mathematical concept of an embedding.
5. 5
   The disappearance of a celestial body, by passing either behind another, as in the occultation of a star, or into its shadow, as in the eclipse of a satellite.
6. 6
   A form of foreign-language teaching where the language is used intensively to teach other subjects to a student.
7. 7
   One's suspension of disbelief while reading, playing a video game, etc. The experience of losing oneself in a fictional world.
8. 8
   A creative relationship with one's social and ecological environment as practiced by the Brooklyn Immersionists.