In rfc793 : page 17 in explaining the No-Operation TCP header option, it is cited:
This option code may be used between options, for example, to align the beginning of a subsequent option on a word boundary. There is no guarantee that senders will use this option, so receivers must be prepared to process options even if they do not begin on a word boundary.
What is the meaning of word boundary in this context?
Since the implementation of this option (No-Operation) in the TCP header depends on the type of OS and varies between different platforms, -please correct me if I'm wrong!-, does the notion of word boundary have something to do with the actual CPU word size?