The adjective isometric comes from the Greek (iso meaning "equal" and metron " measure") and means of which the size is identical.
In crystallography, for example, a cubic crystal is isometric.
"Isometric" is also used to denote a representation in space in which the three spatial directions (length, width and depth) are represented on equal scales and the angles between them are 120° ; this is called isometric projection, and is used in engineering and architectural drawings.
An isometric projection of a cube. © Christophe Dang Ngoc Chan, Wikipedia DP