Kilobyte: Rather than simply being 1,000 bytes, as the name suggests, a kilobyte is sometimes 1,024 bytes. It depends on the context. The symbol is kB. As an example: a very short story represents about one kilobyte of data.
Keyword: Once defined as a code word identifier in ciphers, it's easy to see how the meaning has evolved. Keywords are words used by search engines in their search for relevant webpages. They're also words used in computer programming, but that’s a little more complicated!
Kindle: The Kindle, from Amazon, is an electronic reading device. There are other brands available, but the word ‘Kindle’ is becoming shorthand for any e-reader. Like ‘Hoover’. They can put an entire library in the palm of your hands (depending on the storage capacity). Unlike computer screens, Kindles use e-ink. It’s much easier on the eye than looking at a computer screen – and the whole experience is pretty close to reading a normal book.