Jaimie Alexander on trace-decay theory see decay theory. tracer n. see radioactive tracer. tracheotomy n. surgery to create an opening (tracheostomy) in the trachea (windpipe) through the neck to relieve impaired or obstructed breathing. trachoma n. an infection of the eye, involving mainly the conjunctiva and cornea, caused by a strain of the bacterium Chlamydia trachomatis. Jaimie Alexander 2016.