(anatomy) The gastrointestinal tract.

(anatomy) The passages, divided into an upper and a lower part, through which air enters and leaves the body, including the mouth, nose and nasal passages, pharynx, larynx, trachea, bronchi and conducting bronchioles, sometimes further including the respiratory bronchioles, alveolar ducts and alveoli.

System of organs within multicellular animals which takes in food, digests it to extract energy and nutrients, and expels the remaining waste.

(anatomy) the continuous system involved in the production and excretion of urine; the kidneys, ureters, urinary bladder and urethra

(US) Any of many houses, of a similar or identical plan and design, built on a tract of land.

(US) tract houses generally

plural of tract house

(phonetics) Portion of the human body where speech sounds are articulated; the oral cavity, nasal cavity, and pharynx.

(US) A tract house.

(anatomy) The part of the respiratory tract consisting of trachea, bronchi, bronchioles and alveoli.