“La caña” is the stem of a type of plant (Gramineae): it’s elongated and hollow inside, like bamboo; but the word “caña” has other meanings, too…
¡UNA CAÑA POR FAVOR! ¡NO, MEJOR DOS!
When we go to a bar in Spain and want a beer we can ask for it in a bottle or can, but we also have the option to ask for it in a glass: we ask for “una caña“.
ME HE COMPRADO UNAS BOTAS DE CAÑA ALTA EN LAS REBAJAS
We also use “caña” when we’re talking about boots: if they’re knee-high, they are “de caña alta”, and if they only come up to mid-shin they are “botas de media caña“.
We also have the expressions “dar caña” or “meter caña“, which mean ‘to increase the speed at which you do something, to rush.
-Si no te das caña no podrás acabar el trabajo. / If you don’t hurry up you won’t be able to finish your work.
However, it could also mean ‘to speak badly of someone’.
And last but perhaps the most important: when we want to express our admiration or surprise for something, we say “QUÉ… CAÑA!”
Así que ya sabéis, tenemos “caña” para todos. Pasad un buen día : ))