labelWrap: Boolean

labelWrap specifies whether to wrap or clip label once its width crosses labelMaxWidth.

var  chart =  new  CanvasJS.Chart("container",
{
 .
 .
 axisY:{
	crosshair: {
		enabled: true,
		labelMaxWidth: 50,  
	           labelWrap: true,
		.
		.
	}
 },
 .
 . 
});
chart.render();