This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. Used for or pertaining to focussing.

n. The action of the verb to focus.

v. Present participle of focus.

n. the concentration of attention or energy on something

"These lines of inquiry are not central to the finished work, nor need the audience even be aware of them, though they were central in focussing and clarifying what was being achieved in the work."

focussing   

focus    focussing   

refocusing