Dictionary.net

The consciousness or cognisance by the brain of an impression caused by an external body on the organs of the senses. (F.) Sentiment. It is not necessarily, however, confined to bodies external to us; for we can receive an impression by touching any part of our own body. The body which communicates the impressions needs but to be external to the part impressed. Sensations are divided into external, internal, and morbid. The external are communicated by the five organs of the senses. The internal are such as occur within the body, and arise from some alteration in the function of the part, for the time being. Hunger and thirst are internal sensations, as well as all the natural wants. Morbid sensations may be either internal or external. Objective sensations are produced by impressions on the peripheral nerves; as in vision, audition, &c. Subjective sensations, are such as originate centrically, or in the encephalon,-as tinnitus aurium.