Isobar: a line of equal or constant pressure.

Isobront: a line drawn through geographical points at which a given phase of thunderstorm activity occurred simultaneously.

Isodop: a line of equal Doppler velocity on a radar display.

Isodrosotherm: a line of equal dewpoint.

Isoecho: a line of equal radar reflectivity on a radar display.

Isogon: a line of constant direction of some vector quantity (usually used to describe the wind direction field).

Isoheight: a line of constant geopotential height on a constant pressure surface chart. Because of their ubiquity, they are commonly referred to simply as "contours".

Isohume: a line of constant humidity.

Isohyet: a line of constant amount of precipitation during a given time period.

Isohypse: same as an isoheight.

Isotach: a line of constant wind speed.

Isotherm: a line of constant temperature.

Adaptations of isopleths in other sciences

In sociolinguistics and dialectology, an isogloss is a line on a map showing the boundary between two regional speech variants.