Pulmonary embolism. Pulmonary embolism Pulmonary embolism occurs when a blood clot gets lodged in an artery in the lung, blocking blood flow to part of the lung. Blood clots most often originate in the legs and travel up through the right side of the heart and into the lungs.
WordReference Random House Unabridged Dictionary of American English Â© 2016. tread (tred), v., trod, trodâ¢den ortrod, treadâ¢ing, n. v.i. 1  to set down the foot or feet in walking; step; walk.  to step, walk, or trample so as to press, crush, or injure something (usually fol. by on or upon):to tread on a person's foot.
tread (noun) the part (as of a wheel or shoe) that makes contact with the ground. Synonyms: pace, stride. tread (verb) structural member consisting of the horizontal part of a stair or step. Synonyms: pace, stride. step, tread (verb) put down or press the foot, place the foot For fools rush in where angels fear to tread; step on the brake Synonyms: maltreat, step, tread, pace, abuse, trample, mistreat, ill-use, ill-treat. tread, trample (verb) tread or stomp heavily or roughly The soldiers trampled across the fields Synonyms: tramp down, tread, step, tread down, trample. tread (verb) crush as if by treading on tread grapes to make wine Synonyms: step, trample. tread (verb) brace (an archer's bow) by pressing the foot against the center. Synonyms: step, trample. tread (verb)