clef /klɛf/ a symbol placed upon a staff to indicate the name and pitch of the notes corresponding to its lines and spaces.
staff /stæf, stɑf/ the system of horizontal lines grouped into sets of five (four in the case of plainsong) upon which music is written. The spaces between them are also used, being employed in conjunction with a clef in order to give a graphic indication of pitch
pitch /pɪtʃ/ How high or how low
octave /ɒktɪv, -teɪv/ interval from one A to the next A
Time signature specifies how many beats are in each measure and which note value constitutes one beat.
The beat is the basic unit of time in music.
2: 2 beats in every bar
4: each beat is one quarter note long.
3/4 is 3 quarter notes per measure.
5/2 is 5 half notes per measure.
♯Play the note 1/2 step up (Sharp)
♭Play the note 1/2 step down (Flat)