Speleology or Spelaeology (also spelled spelæology or spelaeology) is the scientific study of caves and other karst features, their make-up, structure, physical properties, history, life forms, and the processes by which they form (speleogenesis) and change over time (speleomorphology). The term speleology is also sometimes applied to the recreational activity of exploring caves, but this is more properly known as caving, potholing, or (not usually by participants) by the largely obsolete American term, spelunking. Speleology and caving are often connected, as the physical skills required for in situ study are the same. In Romania, the term speology is used: this is derived from a Greek word for cave, 'speos', rather than the Latin, 'spelaeum'. Speleology is a cross-disciplinary field that combines the knowledge of chemistry, biology, geology, physics, meteorology and cartography to develop portraits of caves as complex, evolving systems.