/ ˈsaɪləʊ; NAmE -loʊ/ noun ( pl. -os )
1.
a tall tower on a farm used for storing grain, etc.
2.
an underground place where nuclear weapons or dangerous substances are kept
3.
an underground place where silage is made and stored
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WORD ORIGIN
mid 19th cent.: from Spanish , via Latin from Greek siros corn pit.