We are nothing if not subtle. We’ve borrowed a view of this dog’s posterior to talk about a term that appears in several AKC standards:
From the Australian Terrier AKC breed standard: Tan markings (not sandy or red), as rich as possible, on face, ears, underbody, lower legs and feet, and around vent.
From the Brussels Griffon AKC breed standard: Tan: black with uniform reddish brown markings, appearing under the chin, on the legs, above each eye, around the edges of the ears and around the vent;
From the Manchester Terrier: There should be tan under the tail, and on the vent, but only of such size as to be covered by the tail;
From the Cesky Terrier: In show condition the hair at the upper side of the neck, on the shoulders and on the back should not be longer than 1⁄2 inch; it should be shorter on the sides of the body and on the tail; and quite short on the ears, cheeks, at the lower side of the neck, on elbows, thighs and round the vent.
From the Silky Terrier: On the tail the blue should be very dark. Tan appears on muzzle and cheeks, around the base of the ears, on the legs and feet and around the vent.
From the Min Pin: Black with sharply defined rust-red markings on cheeks, lips, lower jaw, throat, twin spots above eyes and chest, lower half of forelegs, inside of hind legs and vent region,
From the Gordon Setter: Black with tan markings, either of rich chestnut or mahogany color.. It must not completely eliminate the black on the back of the hind legs; (6) On the forelegs from the carpus, or a little above, downward to the toes; (7) Around the vent.
By now, you may have guessed to that a “vent” refers to a dog’s “nether region.” The area inside the red outlined triangle (also known as a diamond) is called ‘the vent.’ It includes the dog’s anus, genitals, coat markings and/or color, and anything else that appears in this marked area.
Now you know. And you’re welcome for our having spared you from having to ask in a public setting what a “vent” was (like the time we asked what a “pizzle” was.