Language evolved to describe the natural environment. ‘Water’ meant almost any liquid (except perhaps blood). ‘Tree’ meant any large plant. ‘Earth’ meant any solid. Slowly these words aquired new or more precise meanings or modifications (fire-water, salt-water, pure water; oak tree, shrub, sapling; metal, soil, rock). Words evolved as our knowldge of the world grew. In a natural environment (like a forest) there are many things we cannot name. Beetles, fungi, a type of rain... I will call these natural names.
There is another class of nouns which describe things we have made to perform a function. ‘Saw’ is a serated tool for cutting things. An ‘iPod’ is a device for storing and playing music. We have given these artifacts their names, so we have complete control over them. There is no imprecision in the use of these words. We have made the things and we have made the words to label them. In a built environment, most things we encounter are manufactured, they have precise names. Pen, computer, shoe, table, cup ... I will call these manufatured names.
The differences between these two types of name arise from their relationship to us. Manufactured things have a function which we have devised, and they are defined by that function. Natural things do not have a purpose related to ourselves and so cannot be defined in this way. Because we have an intimate relationship with the things and the words we have made, we have more confidence in manufactured names than natural names.