A snack between breakfast and lunch is commonly known (UK) as
'elevenses'.
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It relates to a break taken at work around 11am, or just more
generally to a morning tea or coffee break.
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Depends on where you live. Some people have breakfast , lunch ,
and dinner. Some have breakfast , dinner, and supper . Just go
along with the prevailing custom, because if you want to throw in
brunch, elevenses , tea etc, you can make yourself nuts.