A word with an empty slot in front of it, waiting for a number. Drop a figure in and the word means the one that comes to that much: a three-pounder fish, a twelve-pounder gun, a million-pounder player.
From pound plus the agent ending -er, which came into English through Old English -ere and is used to name the one that does or has something. The number in front supplies what the pound counts.
這一組是 pound 加上字尾 -er。-er 從古英文的 -ere 一路傳下來，用來指「做那件事或具有那個性質的那一個」。前面的數字負責說明 pound 算的是什麼——磅數，或者英鎊數。
Wiktionary etymology trees supplied in this packet (source_ref kaikki:3f6f69a190036ae4:1506859573 and :1506865600)
Two branches
數字＋pounder＝那麼重的那一個
填進空格的是磅數，整個字就在講重量。
noun · B2
Joined to a number, a -pounder is a person, animal, fish, or thing that weighs that many pounds. A three-pounder weighs three pounds, and a quarter-pounder is a burger made with a quarter of a pound of beef.
幾磅重的那一個
數字＋pounder＝那麼貴的那一個
空格裡填的不是重量而是價錢，用的是 pound 當錢的那個意思。造字方式完全一樣，只是量的東西換了。
noun · C1
Joined to an amount of money, a -pounder is a person or thing that costs that many British pounds. A million-pounder is a player, a house, or a deal costing a million pounds.
值幾英鎊的人或物