Yes, as in the same way, when a dot is put after a minim becomes a dotted minim, a dot after a minim rest makes it a dotted minim rest.
Its an abbreviation for Marcato, which means that the music should be emphatic or accented.
I can't think of any commonly used musical terms beginning with Y, although I can just about convince myself that I once say "Yearningly" in a piece. I may be making that up, though.
One phrase that's heard frequently in jazz circles but won't appear in an arrangement is "Yeah, man."
banjo, banjos soprano, sopranos tango, tangos oratorio, oratorios alto, altos solo, solos concerto, concertos intermezzo, intermezzos (or intermezzi, depending on how sophisticated you feel like making believe you are) staccato, staccatos largo, largos tempo, tempos (when did you last hear tempi?) capo, capos
morse code has nothing to do with music but if u were to say it . would be short note and - would be long note