terazosin: antihypertensive drug (trade name Hytrin) used to treat high blood pressure
alpha blocker: any of various drugs that block alpha-adrenergic receptors; used in treating benign prostatic hyperplasia; relaxes the muscles of the prostate and bladder
sidelight: light carried by a boat that indicates the boat's direction; vessels at night carry a red light on the port bow and a green light on the starboard bow