The ornamental design for a portableterminal, as shown and described.
FIG. 1 is a front elevational view of the portable terminal;
FIG. 2 is a rear elevational view thereof;
FIG. 3 is a left side view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a top plan view thereof; and,
FIG. 6 is a bottom plan view thereof.
The broken line showing of the remainder of the portable terminal is directed to environment and is for illustrative purposes only; the broken lines form no part of the claimed design.