CEDICT
magnet (piece of material that attracts some metals by magnetism) (Classifier: 塊／块 m c; 嚿 c)
Wiktionary
以天然磁鐵礦加工製成，或以鋼、合金鋼經磁化後製成的磁體。具有吸引鐵、鈷、鎳等金屬的性質。
重編國語辭典
磁石
維基詞典
Earth is like a big magnet.
The earth is like a big magnet.
Source: Tatoeba