Definition
Kerning
Kerning is the adjustment of space between two specific letters, so pairs like AV or To do not leave a visible gap. It is a per-pair fix, not a setting you apply to a whole paragraph.
Every well-made typeface ships with a kerning table telling the renderer to tighten or open particular pairs. You mostly notice kerning when it is absent: display type set large, or a font used outside its intended software, shows loose holes beside diagonal and round letters. In body text at 10–12 pt the built-in table is enough and manual kerning is a waste of a day — it is a cover-and-title-page concern, not a novel-interior one.
Related tools & guides
See it handled in your own manuscript
Ceeryo sets your .docx as a book — justified and hyphenated text with widows, orphans and rivers controlled, drop caps, running heads — and shows you every spread before you pay anything.