What is parquet flooring?
Parquet is wood flooring laid in a pattern instead of straight rows. That's it. The word just means the blocks or planks are arranged in a repeating geometric design rather than running in one direction.
The two you'll see most often are herringbone and chevron. They look similar but they're not the same.
Herringbone uses rectangular blocks laid at right angles to each other, forming a zigzag. Each block meets the side of the next one. Chevron uses planks cut at an angle so the ends meet in a clean V shape. Chevron looks sharper and more modern. Herringbone is the classic you'll recognise from old period homes, galleries, that sort of thing.
There are other patterns too. Basketweave, brick bond, Versailles. But herringbone and chevron account for most of what people actually buy.
What's it made from?
Parquet can be solid wood or engineered. Most of what's sold now is engineered because the smaller block sizes make solid wood more prone to movement. Engineered parquet stays put better, especially over underfloor heating.
Oak is the standard. You can get walnut, ash, or other species but oak outsells everything else by a wide margin.
Is it hard to fit?
Harder than planks, yes. There are more cuts and the pattern has to stay true across the room. It takes longer and costs more to install. But when it's done well, a herringbone or chevron floor changes the whole feel of a space.