What is "Piano Notes"?

(Figure 1.1)

Every piano has white and black keys, well you all know that. The first key(just right before two black keys) is called note 'C', move to the next key. That note is called D. The next one is E then F-G-A-B. You got the idea right? You can go on like C D E F G A B C D E F.. so on (see Figure 1.2). [But we'll call next (higher scale) 'C D E F G... ' plus ones(C+ D+ E+.....) for better understanding. We'll discuss it later.] Note that C-D-E-F-G-A-B are called naturals. 

(Figure 1.2)

The First Black key AFTER C is called C#(C Sharp), just same as C the first black key after D is called D#(D Sharp). It will be same for all keys. (see Figure 1.1)

(Figure 1.3)

The black key BEFORE 'D' key is called Db(D flat). Same goes for every key, Black key before 'E' key is called Eb. That means C# and Db, D# and Eb, F# and Gb, G# and Ab, A# and Bb are the same keys. (see Figure 1.3)

(Figure 1.4)

If you consider a part of a keyboard C D E F G A B (Usually middle C of the keyboard) then the next higher of its kind will be called 'C+ D+ E+ F+ G+ A+ B+' in notes for better understanding. There will be many cases when we will have to play a wide range of pitches, in that cases we will consider lower pitch C and higher one C+.