physiotherapy.
2 n. — abbreviation
physiotherapist.
Type: 5. Frequency — While meaning 1 is a Canadianism on the grounds of Frequency (Type 5), meaning 2 is much more clearly this type of Canadianism (see Chart 2); physio as an abbreviation of physiotherapist (the person), rather than the profession, has a much higher prevalence in Canada - by almost a factor of 10 - than other locations (see Chart 2).
See also COD-2, s.v. "physio" (1), which is marked "Cdn & Brit. informal".
Images:

Chart 1: Internet Domain Search, 5 Jun. 2013 
Chart 2: Internet Domain Search, 5 Jun. 2013