Investopedia: Event Study - the standard method for measuring how news moves a stock, and the next step for this analysis (comparing AAPL to the market over the same days).
Apple's live product presentation (Macworld, WWDC in June, the September iPhone event). The stock reacts to the keynote because that is when the news becomes public.
Release
The day a product actually ships to customers, usually one to several weeks after the keynote.
Crisis
A public problem that is not a new product: a defect, a cancelled product, or a warning about weak sales.
Closing price (close)
The last price a share traded at when the market closed at 4:00 pm Eastern. All numbers on this site use closing prices.
Split-adjusted price
Old prices divided by later stock-split ratios (2-for-1 in 2005, 7-for-1 in 2014, 4-for-1 in 2020) so that a $702 share in 2012 shows as about $25, the same units as today.
Trading day
A weekday the market is open. "30 days" here means 30 trading days (about six weeks); "90 days" is about one quarter.
Hit / Miss (verdict)
The author's label: a Hit is a product that became a commercial success; a Miss flopped, was cancelled, or caused a public-relations problem.
Average vs. "up after 30 days"
The average can be pulled around by one huge number. Counting how many events were higher after 30 days shows how consistent a pattern is.
Market benchmark (S&P 500)
An index of 500 large U.S. companies. Comparing AAPL to it separates Apple news from moves that affected every stock.
Event study
A finance method that measures a stock's move around a news event minus what the overall market did in the same window (the "abnormal return").
"Sell the news"
A market saying: a stock rises on rumors before an announcement and goes flat or falls when it finally happens, because the news was already priced in.