Usage:
label [ offset default | x,y,z ] atom-spec

Usage:
~label atom-spec

Label displays labels for all atoms in atom-spec. ~Label removes atom labels. The default label information is atom name with any alternate location ID appended, but custom atom labels can be defined using labelopt. Label font, size, and whether to draw labels in front regardless of their Z-offsets (default true) can be set in the Background preferences. The command rlabel shows residue labels. See also: color, 2dlabels, the Actions menu

By default, the offset of a label is automatically adjusted based on the display style of the corresponding atom. The offset keyword allows specifying an absolute offset that will not be adjusted, or a return to the default behavior. The word default can be truncated. An absolute offset is specified by three comma-separated values x,y,z representing distances along the X-, Y-, and Z-axes in the laboratory coordinate system:

• the X-axis is horizontal in the plane of the screen, increasing to the right
• the Y-axis is vertical in the plane of the screen, increasing upward
• the Z-axis is perpendicular to the screen, increasing outward (toward the viewer)

One way to label a bond or pseudobond is to select it and use the Selection Inspector.