The following is a small list of words spelled the way they should be used in the FreeBSD Documentation Project. If the word you are looking for is not in this list, then please consult the O'Reilly word list.
2.2.X
4.X-STABLE
CD-ROM
DoS (Denial of Service)
Ports Collection
IPsec
Internet
MHz
Soft Updates
Unix
disk label
file system
manual page
mail server
name server
null-modem
web server