kilogramo

Kilogramo has been the ghost at this course's feast for some time. When the chapter on quantity needed a plain example of weight, kilogramo had no page yet and failed the vocabulary ceiling; the obvious fallback, kilo, sits down at rank 2396 and failed it harder, so the article ended up talking about peco da pano instead. It arrives now, at rank 1830, and you may consider the debt paid.

The word is worth a moment because it is two productive pieces, not one root. Gramo is the base unit, and kilo- is the SI prefix for a thousand, taken from Greek khilioi. Once you have those, the whole family builds itself and needs no separate memorising: kilometro, kilovato, kilobajto, and downwards through centimetro, milimetro, miligramo. Esperanto uses the international SI prefixes exactly as the metric system defines them, which makes this one of the few vocabulary areas where you already know several hundred words.

In speech, kilo alone is the everyday clipping, as it is in English and French - du kiloj da terpomoj is what anybody actually says at a market stall. Write kilogramo where precision matters, say kilo where it does not, and note that the abbreviation is kg with no full stop and no plural -j.