datum
Explanation
The Joke
The comic is titled "How to Spot a Scientist." It shows two scenarios with identical setups: someone delivers the devastating news, "The data is in and it looks like there were no survivors, not even your family." The non-scientist reacts with anguished screaming: "NOOOO!" The scientist, hearing the exact same news, responds: "The data are in." — correcting the grammar rather than reacting to the tragic content.
The Humor
The joke plays on the well-known pedantic distinction between "data is" (treating "data" as a mass noun, common in everyday English) and "data are" (treating "data" as the plural of "datum," which is technically correct in scientific usage). The humor comes from the scientist's priorities being so skewed toward grammatical precision that even in the face of the worst possible personal news, their instinct is to correct the grammar rather than process the emotional content. It's a loving satire of the stereotypical scientist's obsession with technical correctness over human feeling, a theme Weinersmith returns to frequently in SMBC.