The ornamental design for a taillamp (outer), as shown and described.
FIG. 1 is a front perspective view of a tail lamp (outer) showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a side view thereof;
FIG. 5 is a top view thereof; and,
FIG. 6 is a bottom view thereof.
It will be understood that the broken lines shown in the drawings illustrate portions of the tail lamp (outer) that form no part of the claimed design.