Suppose that on the first floor of a building, there are three separate apartments numbered 1, 2 and 3 respectively. How can I refer to one of them when writing a postal address? I am wondering if there is any need to mention words like "apartment" or "unit" before the apartment number. Which one is more appropriate to use?
"Apartment 2, first floor"
"Unit 2, first floor"
"2, first floor"
"2 first floor"
"2 1st floor"
I also found this entry on Wikipedia which suggests that the words "lot" and "unit" can be used before the apartment number in Malaysia. (My question is more about American English though):
Salutation, Name of recipient
Name of Position & Department (if applicable)
Unit/Lot number, Building name/Commercial area
Lot number (for building), Street name
Postcode Post office/Mail centre
Lot 323, 1st Floor, Bintang Commercial Centre
Any advice would be appreciated.