To see the official definition and see free tutorials:
WordPress is an online, open source website creation tool written in PHP. But in non-geek speak, it’s probably the easiest and most powerful blogging and website content management system (or CMS) in existence today.
But in reality ‘it is a lot more’ no in fact I would say ‘ it is a lot more!’
Word press is used by 74,652,825 wib sites world wide so it’s a popular base to build a company web site or the best start you will have to build your new on line successful business, and best of all the system is free!