When You're the One Canceling a Flight. In defense of Spirit, most airlines operate on razor thin margins and refund dollars do add up. Even airlines that allow refunds-generally only under very special circumstances-may make you jump through hoops and even pay a fee.
Medical Definition of receptor. 1  1: a cell or group of cells that receives stimuli : sense organ. 2  2: a chemical group or molecule (as a protein) on the cell surface or in the cell interior that has an affinity for a specific chemical group, molecule, or virus.
receptor, sensory, n receptor system built on the theory that receptor organs are specialized and respond to the law of specific nerve energies; i.e., each type of end-organ, no matter what stimulus is applied, will respond (if it responds) with only a single appropriate type of sensation.. a molecule on the surface or within a cell that recognizes and binds with specific molecules, producing a specific effect in the cell; e.g., the cell-surface receptors for antigens or cytoplasmic receptors for steroid hormones. 2. a sensory nerve ending that responds to various stimuli.