The Rope (Symbol)
The most obvious symbol in the film is surely the titular rope. The rope is the weapon that the two murderers use to kill David. Ropes are household items used to tie things together, but here the rope becomes a murder weapon, inextricably binding the two men together. It symbolizes the violence of which both Phillip and Brandon are capable. The fact that they can take a normal and innocuous object and turn it into a violent weapon shows the extent to which they will go to establish their superiority. The rope is re-signified again when Brandon chooses to put it in the drawer, insisting that it is just a rope. He then ties up Mr. Kentley's books with it, exerting his control over the evening and exploiting his dominance over the man. As Kentley does not know that the rope is the object that the two men used to kill his son, the rope symbolizes Phillip and Brandon's secret, as well as his own ignorance.
The Metronome (Symbol)
When Cadell confronts Phillip about why he lied about wringing the chickens' necks, Phillip begins to play the piano anxiously. Cadell is made exceedingly suspicious by Phillip's tense behavior, and places the metronome atop the piano while Phillip plays. Phillip becomes more and more anxious about the ticking sound of the metronome, and exclaims that he cannot play along with it. Phillip is not only out of time with the metronome literally, but he is so anxious that he has become suspiciously out of sync with the lighthearted tone of the party. Thus, the metronome symbolizes Cadell's apprehension of the boys' plot, by revealing Phillip's unease and overwhelming fear. Its relentless ticking symbolizes the fact that it will only be a matter of time before Phillip and Brandon are caught.
Light (Symbol)
The question of light comes up several times in the film. After they kill David, Brandon orders Phillip to open the blinds, which Phillip hesitates to do. In this instance, light symbolizes bringing their deed into view, literally "bringing to light" their murderous act. While Phillip is hesitant to bring light into the room, Brandon is not so worried about it. Indeed, he is almost proud of the fact that they killed their old friend in the middle of the day. Then later, at the party, Phillip does not want to turn on lamps at the party, further symbolizing his fear of being seen or caught as a murderer. Finally, when Cadell returns to the apartment, but before he has found David's body, he suggests that whatever happened to David must have happened "in broad daylight." The fact that the murder happened in the light of day signifies the murderers' belief in their own superiority. The fact that Brandon does not shy away from the light suggests that he has no shame about their deed. Phillip, on the other hand, wants to stay in the dark, suggesting that he is scared and ashamed.
The Dinner Party as Funeral (Allegory)
Dinner parties are sights of lighthearted conversation, a shared meal, and enjoyable togetherness. Everyone who comes to Brandon and Phillip's dinner party expects to have a normal evening, but there is a disturbing secret beneath the surface. The chest on which dinner is served is secretly hiding the dead body of the guest of honor. David's father, aunt, girlfriend, friend, and former housemaster all eat off the surface and gather around it. Thus, the dinner table—usually symbolic of coming together and shared enjoyment—becomes a funeral pyre. The chest is not a gathering place, but a tomb. The dinner party, usually an allegory for life and shared experience, secretly becomes a funeral, a gathering around a feast atop a coffin.
Phillip's Broken Glass (Symbol)
After they murder David and before the dinner party, Brandon examines the crystal glasses on the table and comments on their worth. In this moment, the viewer sees Brandon's detachment and remorselessness about his horrible deed. Then, early on in the dinner party, Mrs. Atwater initially mistakes Kenneth for her nephew David. While it is an honest mistake, it alarms Phillip, who accidentally breaks the glass in his hand. The camera pans over to Phillip's hands, which are cut and bloodied from the broken crystal. In this moment, the broken glass symbolizes Phillip's distress and anxiety. He is so tense from the secret that he must keep that he accidentally breaks the delicate crystal that Brandon recently admired. While it is ethical for Phillip to feel so anxious about their deed, his anxiety is also what ends up revealing their crime. Thus, the broken glass symbolizes the way that Phillip's conscience and worry only ends up hurting him more.
