I’ve been remiss not to talk about prepositions yet, but they can be tricky. For instance, once you learn that i means in, or possibly at, it’s confusing to then know that in telling the time, ten to eight is tio i åtta. So I’ll start with an easy one: mellan = between.
Apart from the obvious, mellan also appears in expressions such as Mellanamerika (Central America), mellanmjölk (medium-fat milk), and mellanmål (snack, literally between-meal).
Mellandag, originally meaning any days between two points in time, has since the late 1800s come to refer to the days between Christmas and New Year (see SAOB for the history). But now the most common use seems to be in the expression mellandagsrea, which Norstedts translates as year-end sales (so they can extend well into January).
A specific sort of mellandag is the klämdag, which is a working day that falls between a public holiday and a weekend (so a common time to choose to take a day off work). From klämma, to squeeze, so literally a squeeze-day.
words from sweden 