10.12 The point command
The point command places a single point on a multiplot canvases, in the same style which would be used when plotting a dataset on a graph with the points plotting style. It is useful for marking significant points on technical diagrams with crosses or other motifs.
The point command that the position of the point to be marked be specified after the at modifier. A text label to be attached next to the point may optionally be specified using the same label modifier as taken by the plot command. A with modifier may then be supplied, followed by any of the style modifiers: color, pointlinewidth, pointsize, pointtype, style.
The following example labels the origin as such:
set texthalign left set textvalign centre point at 0,0 label "The Origin" with ps 2