Instillation (noun)
The act of instilling; also, that which is instilled.
Installation (noun)
An act of installing.
Installation (noun)
Something installed, especially the whole of a system of machines, apparatus, and accessories, when set up and arranged for practical working, as in electric lighting, transmission of power, etc.
Installation (noun)
A work of installation art.
Installation (noun)
A grouping of facilities that constitute a permanent military base
Wiktionary