From WordNet (r) 2.0 (August 2003) [wn]:
shopping
n : searching for or buying goods or services; "went shopping
for a reliable plumber"; "does her shopping at the mall
rather than down town"
From The Collaborative International Dictionary of English v.0.48 [gcide]: Shop \Shop\, v. i. [imp. & p. p. Shopped; p. pr. & vb. n. Shopping.] To visit shops for the purpose of purchasing goods. [1913 Webster] He was engaged with his mother and some ladies to go shopping. --Byron. [1913 Webster]