Hi, Just read postings on these 2 topics but I don't know exactly what they are. I would appreciate some explanations from my fellow dancelovers. Thanks!

Imlovinit. This has been on several times before. All dance music should be eight bar phrsed, with a four bar introduction. Think of a book where each page is one bar of music and there are eight pages to one chapter. If you can count in a 4/4 which means 4 beats to 1 bar Count 1234 2234 3234 all the way throught to eight you will detect a change in the music on the seventh and eighth bar letting you know that a new phrase is coming up. Your choreography should be adjusted accordingly.
Being in Rhythm would mean in the case of a Feather Step in the Foxtrot your preperation step will be on 3 4 and not 1 2. If you were to lead off on 1 2 and the first of your feather on 3 4 you are in time but out of Rhythm.. Something simple to prove a point, In the Quickstep a Quarter Turn , starting on the man's RF Followed by a progressive Chasse and a Lock Step will bring you out of rhythm. Two full Lock Steps will bring you back. Another way. We sometimes see a single Syncopated Lockstep Q & Q which will also allow you to stay in rhythm and is counted
3 & 4 .. Happy Counting.

I have/had been a musician for more than 10 years and a dancer for almost one year. Although I really haven't gotten into discussing musicality and phrasing as it relates to dance with my instructor, I am taking an educated guess here and please, those of you who have been studying dance or have degrees in dance, correct me if I'm wrong.
In layman's term musicality (musical sensitivity) as it relates to dance is how you relate to and express yourself through the music. It's not enough to just feel the music. You need to show the audiences through movements (not moves or steps) and expression what you feel or how the music makes you feel.
The previous poster has touched on the what phrasing is, but I wanted to add that you should be careful not to have any fast rules about how many bars make up a phrase. A phrase is a sequence of bars and notes intended to have some sort of meaning. A lot of times composers will vary the length of each phrase to add variety to the music. For the dancer, the length of your sequences of moves should coincide with the length of each musical phrase and it ties into musicality.