ran·dom
/ˈrændəm/ Show Spelled[ran-duhm] Show IPA
–adjective
1.
proceeding, made, or occurring without definite aim, reason, or pattern: the random selection of numbers.
2.
Statistics. of or characterizing a process of selection in which each item of a set has an equal probability of being chosen.
3.
Building Trades.
a.
(of building materials) lacking uniformity of dimensions: random shingles.
b.
(of ashlar) laid without continuous courses.
c.
constructed or applied without regularity: random bond.
–noun
4.
Chiefly British. bank3 (def. 7b).
–adverb
5.
Building Trades. without uniformity: random-sized slates.
—Idiom
6.
at random, without definite aim, purpose, method, or adherence to a prior arrangement; in a haphazard way: Contestants were chosen at random from the studio audience.
http://dictionary.reference.com/browse/random
I hope this can clear things up for you.