chair: silla, asiento
couch: canape (with an accent on the 'e')
"el sillon" the arm chair
Unas sillas
You could say "¿Cuántas sillas hay en la clase?"
sillas
If you meant "Las Sillas" it means the chairs
katalina. some say katerina, but that is slavic.
In spanish you would say Kathy(put emphasis on the vowels), if it's a name it usually is the same. There are some cases in which it is not though.
You could say "¿Cuántas sillas hay en la clase?"
sillas
You can say "dos sillas", pronounced "dhos SEE-yahs". Or "dos asientos", pronounced 'dhos assYEntoss'.
sillas
If you mean 'furniture' (chairs, tables, etc.) - mueble(s) (moo-AY-blay(ss))
SKU is stock keeping unit. Every product is given a unit in which it is accounted. In case of distance, we say some distance as meter, KM and so on. Similarly say for example in case of chairs, they say 10 chairs makes 1 TPN or ABC which is the stock keeping unit for chairs. If they say they have 10 ABC which means 100 chairs available.
To say 'I have some shoes' in Spanish, you would say 'Tengo unos zapatos.'
To say 'I have some folders' in Spanish, you would say 'Tengo unas carpetas.'
To say 'I have some calculators' in Spanish, you would say 'Tengo unas calculadoras.'
Try the website spainexpat.com. This website does not specifically specify dining chairs for restaurants but it does specialize in Spanish style furniture. Hopefully there will be some commercial furniture on this website. I could not find another website in this category.
To say 'I want some folders' in Spanish, you would say 'Quiero unas carpetas.'
Same "Portafolio" in spanish. In some places you can say "Valija".