Mathematics term for a symbol or variable that does not have a fixed value, often used in algebra and polynomial rings.
Let X be the indeterminate of the polynomial ring.
未知数 is an unknown quantity to be solved for, whereas 不定元 is a formal symbol without a specific value.
Compound of 不定 (indefinite, indeterminate) and 元 (element, variable). The exact historical derivation is uncertain; the term is a modern mathematical coinage.