S: (n) countersink (a hole (usually in wood) with the top part enlarged so that a screw or bolt will fit into it and lie below the surface)
S: (n) cup (the hole (or metal container in the hole) on a golf green) "he swore as the ball rimmed the cup and rolled away"; "put the flag back in the cup"
S: (n) ear hole (a hole (as in a helmet) for sound to reach the ears)
S: (n) eye (a small hole or loop (as in a needle)) "the thread wouldn't go through the eye"
S: (n) eyelet, eyehole (a small hole (usually round and finished around the edges) in cloth or leather for the passage of a cord or hook or bar)
S: (n) siamese, siamese connection (an inlet with two or more couplings to which a hose can be attached so that fire engines can pump water into the sprinkler system of a building)
S: (n) V neck (the neck of a garment has the shape of the letter V)
S: (n) pass-through (an opening that resembles a window between two rooms (especially a shelved opening between a kitchen and dining room that is used to pass dishes))
S: (n) window (a transparent panel (as of an envelope) inserted in an otherwise opaque material)
S: (n) window (an opening that resembles a window in appearance or function) "he could see them through a window in the trees"
S: (n) window (the time period that is considered best for starting or finishing something) "the expanded window will give us time to catch the thieves"; "they had a window of less than an hour when an attack would have succeeded"