720p refers to the vertical resolution: 1280×720 pixels. It is considered HD (High Definition) but not Full HD (1080p).
The file you've specified, "THOR 2011 Dual Audio -ENG-HINDI- 720p x264--PHDR--.mkv," suggests that the movie is available in a high-quality, compressed format. Here's a breakdown of the technical details: THOR 2011 Dual Audio -ENG-HINDI- 720p x264--PHDR--.mkv