Definition from Wiktionary, the free dictionary
- Several members of the Convolvulaceae family; climbing plants with trumpet shaped flowers.
- (informal) An involuntary erection present on waking.
2003, Ray Puxley, Britslang: An Uncensored A-Z of the People's Language, Including Rhyming Slang, Robson, published 2003, page 326:
- Morning Glory (Penis) Would appear to refer to one that stands tall and erect on waking.
2011, Michael Kantor, Now That You're Out, page 64:
- Like any man he wakes up with a morning glory. He precums.
- A rolling cloud in the shape of a cylinder.
erection present on waking — see morning wood