Urban Dictionary defines Elevenses as
The name for a traditional English requirement for a hot beverage, usually tea or coffee and a light, sweet snack to go with it, usually biscuits. The urge arrives around 11am, hence the name, and is used to fill the gap between breakfast and lunch.
"I'm starting to feel a little peckish, is it time for elevenses yet?"
Sachet with teabag-like tag, "Baby Dunn is Brewing"
Once they have stickily munched their elevenses, Pooh says that he had better be off
Elevenses is a traditional little mid-morning snack, complete with tea and often something sweet like a biscuit (translation: cookie), iced bun or slice of cake. Just a little something to get you over the hump until lunchtime. It’s a little respite that the Brits take seriously.
Apparently, Winnie the Pooh enjoyed some honey on bread and condensed milk for elevenses and Hobbits eat elevenses to break up the time between their second breakfast and lunch.
I highly recommend Elevenses as a great baby shower theme!