n. — Law
an enclosed area in a courtroom where a witness sits or stands to gives testimony.
Type: 2. Preservation — The term witness box is used in the UK and other Commonwealth countries (see Chart 1) and is a preservation from British legal usage. In the US, however, the area for the witnesses is generally called the "witness stand" (see Chart 2) or simply the "stand" (see OED-3, s.v. "witness-box" & "witness-stand").
See also COD-2, which labels the term "Brit. & Cdn. (also esp. N Amer. witness stand) and specifies the term witness box as official use in Canadian courts. As Chart 2 shows, "witness stand" is predominantly American.
- The relatively small difference between .ca and US domains would not warrant the declaration of a Type 2 Canadianism if the term were not the official term in Canada. The term is obviously used in the US as well (see Chart 1).
Images:

Chart 1: Internet Domain Search, 19 Oct. 2012 
Chart 2: Internet Domain Search, 19 Oct. 2012