1. an area or object that is the focus of a process, inquiry, or activity.

2. the goal object in a task. For example, the target in a visual search might be to find a letter S in a randomly arranged array of letters. In some concept-discovery tasks, the target is the rule that classifies objects as belonging or not belonging to a category. When a search has more than one item as its goal, these are known as the target set.

3. a tissue, organ, or type of cell that is selectively affected by a particular hormone, neurochemical, drug, or microorganism.

4. a neuron that attracts the growth of the dendrites or axons of other neurons toward it.

5. in parapsychology experiments, the object or event that the participant attempts to identify in tests of clairvoyance, the message that he or she attempts to receive or respond to in tests of telepathy, or the object that he or she attempts to influence in tests of psychokinesis.