the.com/eigenvalue

means In linear algebra, the special scalar by which a vector gets stretched or shrunk (but not redirected) when a matrix acts on it — the value λ satisfying Av = λv.

from A half-German, half-English hybrid born in the early 20th century. The 'eigen-' is German for 'own' or 'characteristic' — as in something proper to a thing itself — so an eigenvalue is literally a matrix's 'own value.' Mathematicians long called these 'characteristic values' or 'proper values,' but the German term, championed especially in the quantum-mechanical work of David Hilbert and his circle, stuck so firmly that English simply adopted 'eigen-' wholesale rather than translate it, spawning a whole family: eigenvector, eigenfunction, eigenstate.