The use of the word torture in Q-CATs work is that given in the UN Convention (below), which covers state action and other action taken by persons acting in an official capacity.
The United Nations Convention Against Torture (UNCAT)¹
The UN Convention, the full title being The United Nations Convention Against Torture and Other Cruel, Inhuman and Degrading Treatment, was drafted in December 1984 and came into effect in June 1987.
Article 1. “…the term ‘torture’ means any act by which severe pain or suffering, whether physical or mental, is intentionally inflicted on a person for such purposes as obtaining from him, or a third person, information or a confession, punishing him for an act he or a third person has committed or is suspected of having committed, or intimidating or coercing him or a third person, or for any reason based on discrimination of any kind, when such pain or suffering is inflicted by, or at the instigation of or with the consent or acquiescence of a public official or other person acting in an official capacity.”