Are there any American Christian denominations that refer to the days of the week by alternate names? At this time of year Bible and Christianity fora are full of posts hinting that Christians who celebrate Christmas are guilty of paganism because it coincides with some pagan holiday celebrated in antiquity.

Given the same line of reasoning, do any (presumably very conservative) Christian denominations in the United States refer to any of the days of the week with alternate names?  Wednesday, for example, is named after the Norse god Odin; Thursday, after Thor; etc.

I believe that the original name days in Latin referred to the days of the week by number, with Monday being the second day (secunda), etc.  This custom persists in Portuguese, with Monday through Friday being referred to by ordinal numbers (Segunda-feira, Terça-feira, ... Sexta-feira).

I know that it seems rather fanatical, but are there some denominations that, in order to avoid saying something roughly equivalent to "We're having a Bible study on Thor's day", have come up with alternate names for some days of the week?
Historically, the Religious Society of Friends&mdash;commonly known as Quakers&mdash;objected to the common names of week days and of months, for exactly the reason you bring up. The website of the Iowa Yearly Meeting has a discussion of this, but in practice the names are quite simple. The week-day names are "First Day" through "Seventh Day" for Sunday through Saturday respectively. Similarly the months are "First Month" through "Twelfth Month" for January through December.

As the web page indicates, many Friends have come to the decision to use the more common names of the days and months, reasoning that the pagan overtones of the names have vanished in modern usage.