Why do we say tonight in English? When you think about it, it’s fairly unusual. Last night makes sense, and so does tomorrow night. But tonight? Where does that come from?
Actually, it’s quite simply constructed of the word to and the word night stuck together. Of course that would be a weird way to use to by modern standards, as we often associate to with movement. But in Middle English, to could also mean at or on in some contexts. It seems odd now, but if you think about prepositions like to, at, in, or on, they’re usually used in many different contexts and don’t have their own inherent meanings, so to being used differently in the past isn’t so strange.
Basically then, tonight meant at night, specifically the coming night. There aren’t many other words that show traces of this use of to apart from of course today and tomorrow. Morrow originally meant the next day, and tomorrow therefore the next day after today. These terms were originally written as two separate words, with to night becoming to-night in the 18th century, and then tonight in the early 20th century.
Unsurprisingly, tonight is quite confusing for learners of English, as it doesn’t seem to follow any particular logic. Often people will say this night, as that’s what the equivalent in their native tongue would translate to. Today actually doesn’t cause many problems, as many languages have a unique word to mean today, rather than just the equivalent of this day, so having the same situation in English isn’t such a big deal. And tomorrow isn’t confusing as morrow isn’t commonly used as a word on its own anymore, so it also just seems like a unique word meaning the day after today.
Tonight though, catches a lot of people out, especially because last night and tomorrow night make sense. Though last night is a bit odd, isn’t it? Put the before it, and see how the meaning changes dramatically. Last of course can mean both most recent and final, which are usually quite different. Curiously, it originally meant most recent, and was a contraction of the Old English latost, meaning latest (circa early 13h century). It was seemingly only in the 14th century that it came to mean final, coming from the sense of latest before the end.
They’re such simple words, today, tomorrow, last, and latest, but they’ve got a surprisingly complex history.
Anyway, whatever you’ree doing tonight, enjoy it like it’s your last one!