The Spanish word for cardboard is la cartulina.
cardboard, pasteboard, cartoon, painting or drawing on strong paper
Yes. Cardboard is one word.
Caja de cartón
yes
You say "cartón" or "cartulina".
Unfortunately, there is no actual scientific word for cardboard
Use google translator, or cardboard fish.
A word that can be added to "card" to create a new word is "board," resulting in the word "cardboard."
That is one word. According to the English Dictionary it currently is.
boxes
The spanish word for guitar is Guitarra. This English word came directly from the Spanish word, but it is not a Spanish word any more than the Spanish word is an Arabic word. "qutar" or a Greek word Chirara.
The spanish word for did is hizo.