Originally Posted by demo5
I have a wedding which begins at 4. The invitation says black tie, which is what I am wearing, but it got me thinking as to what should be worn before 6. I would have though that a morning coat isn't the appropriate item.
Except in an ever diminishing range of geography and location, there is almost an exact correspondence in a non-historical discussion of formal and semi-formal wear between being correct and being pedantic.
In the context of a social event where you are asked to dress semi-formally in dinner clothes at 4PM rather than after 6PM, there really is no answer to the question of how one should dress otherwise.