This word is not acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. The act of rendering sectional in scope or spirit.

n. the act of dividing or partitioning; separation by the creation of a boundary that divides or keeps apart

"The Sanctus once again makes use of the sectionalization, this time introducing another tenor and bass duet for the ‘Pleni sunt caeli’."

separation   

subdivision    septation    zoning