Skip to Main Content

We have a new app!

Take the Access library with you wherever you go—easy access to books, videos, images, podcasts, personalized features, and more.

Download the Access App here: iOS and Android


(tap′ing) [1tap] Percussion (3).

muscle t. Tapping the skin over the belly of a muscle to recruit more motor units and facilitate contraction. It is usually performed manually over muscles weakened from neurological injury.


(tap′ing) [2tap] The withdrawal of fluid from a body cavity. Examples include paracentesis and thoracentesis.


(tar) A dark, viscid mass of complex chemicals obtained by destructive distillation of tobacco, coal, shale, and organic matter, esp. wood from pine and juniper trees.

coal t. A tar produced in the destructive distillation of bituminous coal. It is used as an ingredient in ointments for treating eczema, psoriasis, and other skin diseases.


(tă-ranch′ŭ-lă) [L. tarantula fr. Italian tarantola fr. Taranto, an Italian seaport on the Gulf of Taranto] A large venomous spider of the family Theraphosidae. It is feared by many people, but its bite is comparable in severity to a bee sting. SEE: spider bite; Theraphosidae.


(tar′dĭv) [Fr. tardive, tardy] Delayed, esp. pert. to a disease in which the characteristic sign or symptom appears late in the course of the disease. SEE: tardive dyskinesia.

TAR DNA binding protein

A protein in the nucleus of most cells that regulates DNA transcription of genes into proteins. Excessive levels of TAR DNA-43 are found in inclusion bodies in neurons in amyotrophic lateral sclerosis (Lou Gehrig’s disease), and some cases of frontotemporal and other dementias.


(tār) The weight of an empty container. That weight is subtracted from the total weight of the vessel and substance added to it in order to determine the precise weight of the material added to the container.


(tārd) A container of known and predetermined tare.


(tar′gĕt) [Fr. targette, small shield] 1. A structure or organ to which something is directed. 2. The part of the anode of an x-ray or therapeutic tube in which electrons from the filament or electron gun are focused and x-ray photons are produced. It is usually made of a heavy metal such as tungsten or molybdenum.

targeting efficiency

In genetic engineering, the percentage of DNA strands that are altered divided by the number that are treated.


(tar′nish) Surface discoloration or reduced luster of metals owing to the effect of corrosive substances or galvanic action. In dental restorations, such action may be enhanced by accumulation of bacterial plaque.



Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.