This is the 164th most frequent French word.
ligne
"Line."
In this context, 'ligne' refers to a railway line or track specifically.
Le train est en ligne, prêt à partir.
The train is on the track, ready to depart.
In this usage, 'ligne' means a line in a graphical or physical sense, such as a drawn line.
Elle dessine une ligne droite sur le papier.
She draws a straight line on the paper.
Here, 'ligne' refers to being connected or online, particularly in a digital or telecommunication sense.