I’ve almost always encountered amplitude as a term in physics, where it’s the size of a wave, but I have heard it a few times as a synonym for largeness, which is literally what it means. It showed up in the mid sixteenth century as a word for being ample, coming from the Middle French amplitude and classical Latin amplitudinem, breadth or extent. The core word here is amplus, which means the largest or spacious, and is of course the origin word for ample. Fun fact: know how Latin usually steals words from Greek? Well, this time they stole it from (okay, technically it evolved from) Proto Italic, where the word is amlo-, or able to seize. Not sure how it got from seize to large, but that’s words for you.
Latitude showed up in the late fourteenth century meaning breadth, which is the second time in this series that we’ve heard that word. It comes from the Old French latitude and classical Latin latitudo, width. So at least that makes sense. It’s from the root word latus, which could mean side, wide, or broad, and is from the Proto Indo European stleto-/stele, spread or extend.
Longitude also showed up in the late fourteenth century, where it meant length or height (so, the opposite of latitude). It comes from the classical Latin longitudo, length, from longus, or as we all know it, long. This means that this word is just long with the -tude suffix on it. It’s weird when words actually make sense.
Altitude makes another that showed up in the late fourteenth century, meaning what it does today, height in the sky. Although back then it referred to the stars in the sky because there weren’t any planes. The word comes from the classical Latin altitudinem, height, and altus, high. The al- is actually a Proto Indo European word for grow or nourish, so this word was always related to height in some way.
Anyway, there are other words that end in -tude—a lot of them, but I don’t really think it’s necessary to go into all of them as there’s nothing new to learn. They’re all verbs or something with -tude on them to make them nouns (like fortitude or multitude). And I’m sure I’ll get to the front part of the word eventually.