Kit

Kit is a short form of the forename Christopher. There are two main types of such shortenings: they are convenient for writing, e.g. in lists; or they are essentially spoken pet-names, and thus informal. (See Conventional abbreviations for forenames.)

Short form	Long form	Informal or written	Other short forms	Remarks
Kit	Christopher	informal	Chris, Kester

There is a list of similar names at Conventional abbreviations for forenames, as well as the category:short names

Note that any informal form may be spelled in different ways. Notably, any spelling listed that ends in '-ie' may be written with the ending '-y', and vice versa.

The playwright Christopher Marlowe (1564-93) was known to his contemporaries as Kit Marlowe.

There is a common noun, kit, meaning loosely 'equipment'. You are advised not use this informal word in academic writing.