Please Explain This To Me

[Jazzin']

Can somebody explain this acoustics physics stuff to me please. I saw this formula but I don't knw what each unit is other than P which is for acoustic pressure.
I believe x and/or t represents Time, and Po represents Original Presure.
What do they all mean, especially w and k?

[Jazzin']

Well, I think I figured it out. p is acoustic pressure, po is original pressure, w is angular frequency and k is wave number.
I had to look into my sister's old physics books. I couldn;t find it on google.