longitudo

Longitudo, longitudinis, f., third declension, from longus with the abstract suffix -tudo. That suffix is a machine: altitudo from altus, latitudo from latus, magnitudo from magnus, multitudo from multus, fortitudo from fortis. All feminine, all declining alike, so learning one pattern buys you the whole set.

It covers space and time equally. The length of a wall, and length of days - longitudo dierum, the Vulgate's way of saying a long life. Geographers later fixed it on east-west extent and then, much later still, on the coordinate, which is where English longitude comes from; classical Latin never means the coordinate, so do not read a map reference into a Roman surveyor.