Definitions for tube foot
Random House Webster's College Dictionary
one of numerous small, tubular processes on the ventral body surface of most echinoderms, used for locomotion and grasping.
Origin of tube foot:
tentacular tubular process of most echinoderms (starfish and sea urchins and holothurians) having a sucker at the end and used for e.g. locomotion and respiration
A locomotor appendage of an echinoderm consisting of a tube with longitudinal muscles, pressurized by water.