A——— is a vertical line that separates measures
A bar line is a vertical line that separates measures in music notation.
A bar line is a vertical line that separates measures.
A vertical line that separates measures is called a bar line or a vertical bar. It is often used in music notation to divide measures or bars. To insert a bar line in music notation, you can use music notation software or by hand on paper.
If you are using music notation software, you can usually find a specific tool or command that allows you to insert a bar line. Typically, you would select the appropriate measure where you want to insert the bar line and then activate the tool or command to add the vertical bar.
If you are writing music by hand on paper, you can simply draw a vertical line or use a ruler to create a straight line to separate the measures. Make sure the line extends from the top to the bottom of the staff, and it should be slightly thicker or darker than the other lines on the staff to clearly differentiate it as a bar line.