amplekso

Amplekso is how much of something there is: the extent of the damage, the scope of a project, the volume of a body, the length of a book in pages. Where English switches word depending on the domain, Esperanto keeps one noun and lets the context choose.

The false seam is tempting and completely wrong. Am- looks like the root of ami, to love, and -plekso looks like it might be a root of its own, so the word reads as something like a love-tangle. It is not. The root is ampleks-, from the verb ampleksi, to encompass or comprise, and the split you can feel is a Latin one - amb- around plus plectere to plait - that had already fused before the word was borrowed.

Note also that this root has nothing to do with ampla or English "ample", which come from a different Latin word, amplus. Two similar-looking families, no shared ancestor.

In use: ampleksa extensive, wide-ranging; ampleksi to comprise, as in la libro ampleksas tricent paĝojn, the book runs to three hundred pages. That last construction is the one to memorise, because it saves a clumsy sentence about size every time.