WordNet (r) 3.0 (2006):

blog
    n 1: a shared on-line journal where people can post diary
         entries about their personal experiences and hobbies;
         "postings on a blog are usually in chronological order"
         [syn: web log, blog]
    v 1: read, write, or edit a shared on-line journal

The Jargon File (version 4.4.7, 29 Dec 2003):

blog
 n.

    [common] Short for weblog, an on-line web-zine or diary (usually with
    facilities for reader comments and discussion threads) made accessible
    through the World Wide Web. This term is widespread and readily forms
    derivatives, of which the best known may be blogosphere.


The Free On-line Dictionary of Computing (30 December 2018):

blog
web log

    (From "web log") Any kind of diary published on
   the web, usually written by an individual (a
   "blogger") but also by corporate bodies.

   Blogging is regarded by some as an important social phenomenon as
   it contributes to the easy exchange of ideas among a large and
   growing international community ("the blogosphere").

   A blog is just a special kind of website.  The home page
   usually shows the most recent article and links to earlier
   articles, the owner's profile and web logs written by the owner's
   friends.  There is usually a facility for readers to add comments
   to the bottom of articles.  Blogs usually provide an RSS feed of
   current articles, allowing readers to subscribe by adding the feed
   to their favourite RSS reader.

   Many sites, e.g. (http://blogger.com/), let you create a blog
   for free.  Many blogs consist almost entirely of links to other
   web logs, some publish original content, a few are worth reading.

   (2013-08-15)