As we go through life, we can become familiar enough with the things in our lives that even a vague description can bring others up to speed on what we're talking about.
And sometimes, that vague description does the job a little better than the actual name we might have for something. For instance, some people might know what we mean if we say our aglets fell off but pretty much everyone will understand us if we say the same about "those things on the ends of our shoelaces."
Without that knowledge, that first word may make it sounds like we're having some kind of medical emergency rather than being mildly inconvenienced.
But as we're about to see, those aglets are far from the only things in life we can all identify but can't necessarily name.