You wake up. It’s 8:30 am, May 31. Your beloved is standing nearby. “Disjune?” you say.
“May,” your beloved replies. “Tomorrow.”
“Tomorrow?” you say. “Why may we not today?”
“May not what?”
“No,” your beloved says. “Dismay!”
“I am dismayed!” you say. “Not only that, I’m hungry!”
“Well, let’s eat, then,” your beloved says.
“You said we may not,” you say, slowly attaining the vertical.
“No, I said we June not. It’s May.”
“If we june not, then let us disjune.”
“I don’t want to diss it,” your beloved says. “It’s not even here yet.”
“Look,” your beloved says, “I can’t deal with this on an empty stomach. Let’s have breakfast.”
“That’s what I was saying,” you say.
At this point you’re awake enough to sort out that perhaps your beloved does not know the word disjune, and you are about to explain it. However, your beloved has already escaped the room and is headed for the kitchen.
You (dear reader) may not know disjune either. But you may know the French word déjeuner, which these days usually means ‘lunch’, and petit déjeuner, which is ‘breakfast’. Well, déjeuner is just the modern French of the same word that has come to us (and especially to Scots, apparently) as disjune. It is formed on the French jeun, as in à jeun ‘on an empty stomach’ and jeûne ‘fasting’, which comes from Latin jejunus, ‘fasting’. (No connection to jeun/jeune meaning ‘young’.) So to disjune is to un-fast, de-fast, or, um, break fast. (Disjune is mainly used as a noun, but has been verbed, though not often.)
Yes, disjune literally means the same as breakfast, etymologically.
It has nothing to do with the month June, though. The month is named after the Roman goddess Juno. Now, it happens that jejunus traces back to a Proto-Indo-European root referring to sacrifice and worship (well, fasting has its religious uses), but Juno does not – it probably comes from roots meaning either ‘heaven authority’ or ‘lifetime authority’.
But that’s all good news, d’you know? It means you can still have breakfast between May 31 and July 1 without any disjunction.