The Collaborative International Dictionary of English v.0.48:

Client \Cli"ent\, n. [L. cliens, -emtis, for cluens, one who
   hears (in relation to his protector), a client, fr. L. cluere
   to be named or called; akin to Gr. ? to hear, Skr. [,c]ry,
   and E. loud: cf. F. client. See Loud.]
   1. (Rom. Antiq.) A citizen who put himself under the
      protection of a man of distinction and influence, who was
      called his patron.
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   2. A dependent; one under the protection of another.
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            I do think they are your friends and clients,
            And fearful to disturb you.           --B. Jonson.
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   3. (Law) One who consults a legal adviser, or submits his
      cause to his management.
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