A hybrid of yesterday and tomorrow. The twocancel each other out, so in the end you just have an unnecessarily elongated form of today.
Employee: "How are you tomterday?"
Customer: "I was doing just great until you fucked everything up by using tomterday. By the way I need a pack of condoms."
when, on a Friday, a teacher or boss starts to say "tomorrow", but realizes that tomorrow is Saturday and nobody will be around to do anything, and so changes halfway through the word to say Monday.
Teacher: "Class, don't forget that your field tripmoney is due Tomonday."
Used during that awkward time between 12:00 am and 3:00 am that that , if still up, many don't know what to say when saying goodnight or goodbye. Synonyms: Later, soon
"Yo man, I'll see you tomorrow."
"Its 2:35 am, do you mean today, or tomorrow."
"....I'll see you tomoday then"