odkazy.seznam.cz is a 6 character word. It is a good domain length and you should make sure that your domain name is easy for people to type and remember.
Top Level Domain
odkazy.seznam.cz is still good but not best as same as .com. This is designed to target a specific country or audience. Remember that you can lose some web traffic to .com version of the domain because people tend to type .com more than any TLD.
odkazy is neither a dictionary word, nor does it contain any dictionary word. People tend to remember dictionary words faster than not dictionary words. However, dictionary words are not required.