citrono

The fruit and the tree. Citrono is the fruit; the tree is citronarbo or citronujo, using the -uj- suffix that grows plants from their produce - the same pattern as pomujo from pomo. Citrona as an adjective covers both the flavour and the colour: citrona suko is lemon juice, citrona koloro is lemon yellow.

Why not "limono". Several European languages call it a limon or limone, and a beginner reaching for the international word often lands there first. In Esperanto limono is a different citrus - the lime - so the two are kept apart deliberately. If you want the sharper green one, that is limeo or limono depending on which dictionary you trust; if you want the yellow one on the market stall, it is always citrono.

Taste vocabulary. The lemon is the standard illustration of acida, sour, exactly as it is in English. Acida kiel citrono needs no gloss. It sits opposite dolĉa and beside amara, and its suko is the one you squeeze rather than drink.