Webster's Revised Unabridged Dictionary · 1913

Client

Client , noun

[Latin cliens, -emtis, for cluens, one who hears (in relation to his protector), a client, from Latin cluere to be named or called; akin to Greek {not transcribed} to hear, Sanskrit cry, and English loud: compare French client. See Loud.]

1.
(Rom. Antiquities) A citizen who put himself under the protection of a man of distinction and influence, who was called his patron.
2.
A dependent; one under the protection of another.
I do think they are your friends and clients, And fearful to disturb you. — B. Jonson
3.
(Law) One who consults a legal adviser, or submits his cause to his management.