n. — Education
a qualified teacher hired to replace a regular teacher who is absent; a substitute teacher.
Type: 2. Preservation — In Canada "substitute teacher" and supply teacher are used at roughly the same frequency (see Charts 1 & 2), with the former being slightly in the lead. Supply teacher is a preservation from Irish and British English. In comparison with the US, supply teacher is more prevalent in Canada, although not as common as in Ireland and the UK (see Chart 1). Substitute teacher is most common in the US (see Chart 2). This is a Canadianism only in the North American context, based on a frequency count three times higher than in the US. It remains to be seen if this distinction is upheld in the 21st century.
See also COD-2, s.v. "supply teacher", which is marked "Cdn & Brit".
See also: serviced
Images:

Chart 1: Internet Domain Search, 4 Jul. 2013 
Chart 2: Internet Domain Search, 4 Jul. 2013