This vocabulary is meant chiefly for people educated outside Europe because, among other things, it explains some aspects of European architecture. But anyone who's interested is welcome to read it, of course :-)
Castle x chateau - Both are residences of local aristocracy.
A castle is a stone fortress built earlier than cca. 1530. A chateau was built after 1530, using bricks. Some chateaus are rebuilt castles. Some chateaus were rebuilt in the 19th century to be made to look like castles.
There are hundreds and hundreds of castles in the Czech Republic - I heard that according to the Guiness Book of Records, the Czech Republic is the most castle-dense country in the world. But I'm not sure about that - it's quite possible that the authorities counted even castles that just consist of one wall nowadays. Honestly, most castles are in ruins.
This is an example of a castle:
The number of chateaus is much smaller - about 120. Most of them have beautiful gardens and parks.
They make for good one-day trip destinations, because it's sort of an unwritten rule in the CzR that chateaus should be made accessible to the public. That's why most of them are furnished with historical furniture and there are guided tours that tell you all about it - how the aristocracy lived, any connections with other European countries' history, and any funny or scary events that might have happened here - be they true or not :-) This way, you can learn about a 18th century mirror that makes you look younger, about a chateau painted red because there's a blood stain on the wall that wouldn't come off (from a man a local landlord murdered), and about a nobleman that was buried alive.
That's why even privately-owned chateaus - by the descendants of the original owners, who got them back from the state (after they were confiscated by the Communists) are mostly like this. If the owners live in them, they only occupy one wing and make the rest accessible to the public. Or, they make them into culture centres or hotels. Chateaus not open for the public are an anomaly here.
Here's a chateau:
Pond (or rybník in Czech) - something between a water reservoir and a natural
lake. More precisely, it's a water reservoir built in the 16th, 17th or 18th
century. Its purpose was to hold water and to grow fish (Czech ryby,
hence the name).
They're often of rectangular shape but
because they've been around for some 400 years, they have old trees growing on
their banks and fit into the countryside perfectly. And so most foreign
visitors mistake them for natural lakes. There are hundreds of them, while
natural lakes are much less numerous - there is just a couple of them in the
Renaissance - The first style in clothing, architecture, music and art that came after Middle Ages (the last style of which was Gothic).
In my country, it was dominant roughly from 1530 to 1630.
Its key word is considered to be "harmony". No extremes. That's why it doesn't make the impression of trying to reach the sky (as the previous Gothic style does - even the clothing with its tall hats), nor to express dramatic emotions (as its successor, Baroque style, does). In architecture, it's more of a style of worldly buildings - like town houses and chateaus. Only a few churches are built in Renaissance style. Although - there are exceptions to every rule:
As to Renaissance chateaus, you'll find them in more remote and less rich areas. That's because they're the oldest ones. Wherever the region was rich, the aristocracy had the money to re-build their Renaissance residence in whatever style was popular at a later time.
If you want to recognize Renaissance buildings as you walk, you can go for the top parts of them - they're usually divided into small "steps" or "waves":
or the buildings are painted with the typical sgraffiti called psaníčka (letters, envelopes):