Pneumatology is the study of spiritual beings and phenomena, especially the interactions between humans and God. Pneuma (πνεῦμα) is Greek for "breath", which metaphorically describes a non-material being or influence.
In Christiantheologypneumatology refers to the study of the Holy Spirit. The English word comes from two Greek words: πνευμα (pneuma, spirit) and λογος (logos, teaching about). Pneumatology would normally include study of the person of the Holy Spirit, and the works of the Holy Spirit. This latter category would normally include Christian teachings on new birth, spiritual gifts (charismata), Spirit-baptism, sanctification, the inspiration of prophets, and the indwelling of the Holy Trinity (which in itself covers many different aspects). Different Christian denominations have different theological approaches.