feeler

Feeler is a term used across several disciplines with distinct but related meanings. In biology, a feeler refers to a sensory appendage that helps an animal explore its environment. In insects, long antennae serve tactile, chemical, and sometimes thermal sensing; in crustaceans, palps and antennules perform similar functions. In some mammals, whiskers are commonly described as feelers and function as tactile probes. Generally, feelers are flexible or extendable structures equipped with receptors or hairs that detect contact, vibrations, temperature, or chemical cues.

In engineering and measurement, a feeler is a thin strip used with a feeler gauge to measure small gaps or clearances between parts. The gauge set includes blades of varying thickness; a user inserts a blade into the gap until it fits with the correct resistance, thereby determining the clearance. Feeler blades are also used in other precision tasks where close tolerances are important, such as alignment or non-contact sensing.

In everyday language, a feeler can describe a person who tests the reaction of others before pursuing a more formal arrangement. To “send out feelers” means to make tentative inquiries to gauge interest or feasibility in a potential partnership, purchase, or project. The term conveys an exploratory, non-committal approach rather than a definite plan.

Overall, feeler denotes both physical sensing structures in living organisms and metaphorical or technical probes used in measurement and social contexts.