Apt - Search Syntax

[Gregory Piñero]

What is the command line equivalent of Synaptic Package Manager's Search?

For example I want to see if there is a matplotlib package and how to
spell it (proper cases and such)

Bonus points for telling me how to find this information for myself in
the future.  I tried the following with no luck:
$ apropos search packages
$ man apt-get
Google search

Thanks,

-- 
Gregory Piñero
Chief Innovation Officer
Blended Technologies
(www.blendedtechnologies.com)