A teraflop measures **speed**, not size — this is the whole point of the word, and the reason it gets mixed up with terabyte. One teraflop means a computer can do a trillion (a million million) calculations of a certain kind every second. The calculations counted are floating-point operations: sums with decimal points in them, the hard kind, the kind you need for weather models, film animation, 3D games and training AI. Ordinary whole-number counting is easier and is not what this measures. You meet the word mostly in two places: when people compare supercomputers, and when game consoles and graphics cards are advertised — a console maker will say its machine does 12 teraflops, meaning it is faster than the last one. Treat that number carefully; it tells you about raw arithmetic power and not much about whether a game actually feels smooth. The plural is teraflops, and awkwardly the singular already ends in s in the fuller form **teraflops** (floating-point operations per second), so you will see both "a teraflop" and "one teraflops" in technical writing. Bigger units exist: a thousand teraflops is a petaflop.

兆次浮點運算（每秒）；台灣談顯示卡、遊戲主機效能時常直接講「幾個 T」或「TFLOPS」。重點是它衡量的是「算得多快」，不是「存得多少」。