For example ...
I can not remember the time before my dad called me "Doodlebug," though sometimes he added some initials: "D. J. Doodlebug." It is the first name I remember, the last name he ever called me. Not long before he died, I walked into his room at the nursing home where he'd gone to die--all systems failing--and he brightened a moment, the drug haze dissipating, and he said, "There's old Doodlebug!"
When I was a child, I had no idea what that word doodlebug meant. (And the initials D. J.? No clue.) I remember asking him once, and he said I reminded him of a little train, a doodlebug, chugging around the house at full steam all the time. That sounded all right. Sort of flattering ... sort of not, too.
Later, after he died, thinking about that name, I checked the OED, and, Dad, are you sure about that train? Here are the other meanings of that word--and how, I guess, they've applied to me.
3. a divining rod or other device supposed by prospectors to indicate the presence of oil, minerals. So, Dad, in what sense was I (am I? have I ever been?) a divining rod? Well, let's stretch the metaphor: I'm now a book critic, looking for treasure on printed pages. I hope I employ tools, though, that are a little more reliable than a forked stick?
4. a prospector for oil, minerals, etc. (See #3)
Dad didn't really have firm nicknames for my two brothers, one younger, one older. I'm not sure why. But I think they've missed out on something.
I still sign "Doodlebug" on all the letters to my mom (sometimes with the mysterious "D. J." as well). My heart leaps up when I behold the word in print somewhere. And when I think of my father, lying there near death, his great athlete's body betraying him, his bright, educated mind struggling to comprehend, his fear surely his greatest enemy, I wonder how he could find the strength to summon that word once again, that word that brought a smile to my face, then broke my heart.