Ties are curved lines that connect notes of the same pitch indicating a single longer note.

Ties are curved lines that connect notes of the same pitch indicating a single longer note.

While ties appear superficially identical to slurs, they do not have the same meaning (slurs connect notes of different pitch).

Ties are used when a single note symbol cannot be used because it would either spill across a bar lines or a major subdivision of a bar. They are also used to create durations for which no single notation exists.