A "triple room" refers to a hotel room that can accommodate three people, typically with an additional bed or larger space to accommodate the extra person. Full definition
Double or triple room with en - suite bathroom. (travelground.com)
Two single room sharing a bath room; One twin room en - suite; One triple room en - suite; One family.. (edlets.com)
The ensuite rooms provide a variety of room configurations with double, twin and triple rooms offering double beds and single beds, or quad rooms offering four single beds. (wikiaustralia.com)