The ornamental design for a socket for extensioncord, as shown and described.
FIG. 1 is a top front right side perspective view of a socket for extension cord, showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The socket for extension cord is shown with a symbolic break in its length. The appearance of any portion of the article between the break lines forms no part of the claimed design.
The broken lines depict portions of the socket for extension cord that form no part of the claimed design.