Question: I am starting to read up on SP development but none of the books I have checked have been able to answer this seemingly simple question.

I am pretty new to the dev side of things and feel like I missed something obvious.

Answer: 
Features make it easier to deploy managed solutions or site customizations to SharePoint. A feature can be just about anything, but more often than not it seems they are ASP.Net wrapped in a solution and deployed to SharePoint. (IMHO)

Check these out, see if they help:

MSDN overvew
<http://msdn.microsoft.com/en-us/library/office/ms460318(v=office.14).aspx>

Channel 9 video
<http://channel9.msdn.com/Shows/Devs4Devs/Building-Features-in-SharePoint-2010>

Step by step guide in blog
<http://weblogs.asp.net/sreejukg/archive/2011/10/27/developing-sharepoint-2010-features-using-visual-studio-2010.aspx>
Feature is a unit of deployment that generally includes content such as .aspx application pages, list schemas, customizations expressed in CAML

I also highly recommend to read Ted Pattisons book: [http://www.amazon.com/dp/0735623201/?tag=stackoverfl08-20](http://rads.stackoverflow.com/amzn/click/0735623201)

Check this Tech-net Article, [Creating SharePoint Features](http://msdn.microsoft.com/en-us/library/ee231541.aspx)  

also MSDN, [SharePoint Feature](http://msdn.microsoft.com/en-us/library/bb861828%28v=office.12%29.aspx)  

and [this link](http://www.dotnetspark.com/qa/3674-what-is-sharepoint-feature-features-are.aspx)