The Lady Janet bought this great old childrens’ book from 1957 called A Hole is to Dig by Ruth Krauss, who also wrote The Carrot Seed, with illustrations by Maurice Sendak. (You could do worse for an illustrator.)
It has these wonderful “operational” definitions, mostly by Kindergarteners, like “A face is so you can make faces,” or “Toes are to wiggle.” Here is a quote from this wonderful book:
“A tablespoon is to eat a table with.”