Buying underwear for any woman can be a bit of a minefield.
Particularly this
bra size thing.
Now, I've read that nearly 80% of
women wear the wrong size bra, but this doesn't mean that you can just guess.
Basically, you've got two choices: buy a bra the same size as she normally wears (after surreptitiously examining the label one morning)
or, engage her help in the - obviously completely scientific - exercise of measuring her size ("just out of interest").
You could then be the first person ever to
buy her the correct size bra!
demi-balconette (what??) - like a balconette, in that it pushes up ... but not like a balconette, in that it doesn't have particularly low-cut cups (I know ... blame Figleaves for this strange hybrid style)
bandeau - a non-underwired bra (see above), which is normally just a rectangular strip of fabric, often with detachable straps
sports - normally non-underwired (see above), but provide a lot of support to stop bouncing when she's exercising
multiway - bras with detachable straps which you can put on as normal shoulder-straps, halter-neck, just a back strap, cross-over straps, etc - according to what the straps on her top or dress are like
strapless - normally moulded (see below); not actually strapless, in that they have just a back strap, so she can wear them underneath strapless dresses; normally come with additional clear shoulder straps (see below)