noun
A formal or technical term for palm reading; less common in everyday conversation than 手相占い.
観掌術は手のひらの線から運命を読み解く。
Palmistry interprets fate from the lines on the palm.
手相占い is the common, everyday term for palm reading, while 観掌術 is a more formal or technical expression.
Composed of 観 (observe), 掌 (palm), and 術 (technique/art). The exact historical derivation is uncertain; it is a Sino-Japanese compound used in technical contexts.