(covers information from several alternate timelines)
A sinus was an anatomical feature of the nose found in several species.
Kali-fal, a Romulan beverage, was known for opening sinuses, even before the first sip, due to its strong aroma. A replicated version of kali-fal failed to live up to Vreenak's expectations, which Benjamin Sisko chalked up to inexperience in replicating Romulan drinks while hosting the Romulan at Deep Space 9 in 2374. (DS9: "In the Pale Moonlight")
In the mirror universe, Klingon Regent Worf found his sinuses to be clear for the first time in years after trying beetle snuff in 2375. He requested Garak procure more for him. (DS9: "The Emperor's New Cloak")